diff --git a/congress_service.py b/congress_service.py
new file mode 100644
index 0000000..e8ec5e3
--- /dev/null
+++ b/congress_service.py
@@ -0,0 +1,68 @@
+"""Congress trading data: member trades and bill search."""
+
+import asyncio
+import logging
+from typing import Any
+
+from openbb import obb
+
+from obb_utils import to_list
+
+logger = logging.getLogger(__name__)
+
+
+async def _try_obb_call(fn, *args, **kwargs) -> list[dict[str, Any]] | None:
+    """Attempt a single OBB call and return to_list result, or None on failure."""
+    try:
+        result = await asyncio.to_thread(fn, *args, **kwargs)
+        return to_list(result)
+    except Exception as exc:
+        logger.debug("OBB call failed: %s", exc)
+        return None
+
+
+def _get_congress_fn():
+    """Resolve the congress trading OBB function safely."""
+    try:
+        return obb.regulators.government_us.congress_trading
+    except AttributeError:
+        logger.debug("obb.regulators.government_us.congress_trading not available")
+        return None
+
+
+async def get_congress_trades() -> list[dict[str, Any]]:
+    """Get recent US congress member stock trades.
+
+    Returns an empty list if the data provider is unavailable.
+    """
+    fn = _get_congress_fn()
+    if fn is None:
+        return []
+
+    providers = ["quiverquant", "fmp"]
+    for provider in providers:
+        data = await _try_obb_call(fn, provider=provider)
+        if data is not None:
+            return data
+
+    logger.warning("All congress trades providers failed")
+    return []
+
+
+async def search_congress_bills(query: str) -> list[dict[str, Any]]:
+    """Search US congress bills by keyword.
+
+    Returns an empty list if the data provider is unavailable.
+    """
+    fn = _get_congress_fn()
+    if fn is None:
+        return []
+
+    providers = ["quiverquant", "fmp"]
+    for provider in providers:
+        data = await _try_obb_call(fn, query, provider=provider)
+        if data is not None:
+            return data
+
+    logger.warning("All congress bills providers failed for query: %s", query)
+    return []
diff --git a/main.py b/main.py
index f2c8e1c..69961c0 100644
--- a/main.py
+++ b/main.py
@@ -37,6 +37,7 @@ from routes_sentiment import router as sentiment_router  # noqa: E402
 from routes_shorts import router as shorts_router  # noqa: E402
 from routes_surveys import router as surveys_router  # noqa: E402
 from routes_technical import router as technical_router  # noqa: E402
+from routes_portfolio import router as portfolio_router  # noqa: E402
 
 logging.basicConfig(
     level=settings.log_level.upper(),
@@ -81,6 +82,7 @@ app.include_router(fixed_income_router)
 app.include_router(economy_router)
 app.include_router(surveys_router)
 app.include_router(regulators_router)
+app.include_router(portfolio_router)
 
 
 @app.get("/health", response_model=dict[str, str])
diff --git a/portfolio_service.py b/portfolio_service.py
new file mode 100644
index 0000000..3fb0dd8
--- /dev/null
+++ b/portfolio_service.py
@@ -0,0 +1,222 @@
+"""Portfolio optimization: HRP, correlation matrix, risk parity."""
+
+import asyncio
+import logging
+from typing import Any
+
+import numpy as np
+import pandas as pd
+
+from obb_utils import fetch_historical
+
+logger = logging.getLogger(__name__)
+
+
+async def fetch_historical_prices(symbols: list[str], days: int = 365) -> pd.DataFrame:
+    """Fetch closing prices for multiple symbols and return as a DataFrame.
+
+    Columns are symbol names; rows are dates. Symbols with no data are skipped.
+    """
+    tasks = [fetch_historical(sym, days=days) for sym in symbols]
+    results = await asyncio.gather(*tasks)
+
+    price_series: dict[str, pd.Series] = {}
+    for sym, result in zip(symbols, results):
+        if result is None or result.results is None:
+            logger.warning("No historical data for %s, skipping", sym)
+            continue
+        rows = result.results
+        if not rows:
+            continue
+        dates = []
+        closes = []
+        for row in rows:
+            d = getattr(row, "date", None)
+            c = getattr(row, "close", None)
+            if d is not None and c is not None:
+                dates.append(str(d))
+                closes.append(float(c))
+        if dates:
+            price_series[sym] = pd.Series(closes, index=dates)
+
+    if not price_series:
+        return pd.DataFrame()
+
+    df = pd.DataFrame(price_series)
+    df = df.dropna(how="all")
+    return df
+
+
+def _compute_returns(prices: pd.DataFrame) -> pd.DataFrame:
+    """Compute daily log returns from a price DataFrame."""
+    return prices.pct_change().dropna()
+
+
+def _inverse_volatility_weights(returns: pd.DataFrame) -> dict[str, float]:
+    """Compute inverse-volatility weights."""
+    vols = returns.std()
+    inv_vols = 1.0 / vols
+    weights = inv_vols / inv_vols.sum()
+    return {sym: float(w) for sym, w in weights.items()}
+
+
+def _hrp_weights(returns: pd.DataFrame) -> dict[str, float]:
+    """Compute Hierarchical Risk Parity weights via scipy clustering.
+
+    Falls back to inverse-volatility if scipy is unavailable.
+    """
+    symbols = list(returns.columns)
+    n = len(symbols)
+
+    if n == 1:
+        return {symbols[0]: 1.0}
+
+    try:
+        from scipy.cluster.hierarchy import linkage, leaves_list
+        from scipy.spatial.distance import squareform
+
+        corr = returns.corr().fillna(0).values
+        # Convert correlation to distance: d = sqrt(0.5 * (1 - corr))
+        dist = np.sqrt(np.clip(0.5 * (1 - corr), 0, 1))
+        np.fill_diagonal(dist, 0.0)
+        condensed = squareform(dist)
+        link = linkage(condensed, method="single")
+        order = leaves_list(link)
+        sorted_symbols = [symbols[i] for i in order]
+    except ImportError:
+        logger.warning("scipy not available; using inverse-volatility for HRP")
+        return _inverse_volatility_weights(returns)
+
+    cov = returns.cov().values
+
+    def _bisect_weights(items: list[str]) -> dict[str, float]:
+        if len(items) == 1:
+            return {items[0]: 1.0}
+        mid = len(items) // 2
+        left_items = items[:mid]
+        right_items = items[mid:]
+        left_idx = [sorted_symbols.index(s) for s in left_items]
+        right_idx = [sorted_symbols.index(s) for s in right_items]
+
+        def _cluster_var(idx: list[int]) -> float:
+            sub_cov = cov[np.ix_(idx, idx)]
+            w = np.ones(len(idx)) / len(idx)
+            return float(w @ sub_cov @ w)
+
+        v_left = _cluster_var(left_idx)
+        v_right = _cluster_var(right_idx)
+        total = v_left + v_right
+        alpha = 1.0 - v_left / total if total > 0 else 0.5
+
+        w_left = _bisect_weights(left_items)
+        w_right = _bisect_weights(right_items)
+
+        result = {}
+        for sym, w in w_left.items():
+            result[sym] = w * (1.0 - alpha)
+        for sym, w in w_right.items():
+            result[sym] = w * alpha
+        return result
+
+    raw = _bisect_weights(sorted_symbols)
+    total = sum(raw.values())
+    return {sym: float(w / total) for sym, w in raw.items()}
+
+
+async def optimize_hrp(symbols: list[str], days: int = 365) -> dict[str, Any]:
+    """Compute Hierarchical Risk Parity portfolio weights.
+
+    Args:
+        symbols: List of ticker symbols (1-50).
+        days: Number of historical days to use.
+
+    Returns:
+        Dict with keys ``weights`` (symbol -> float) and ``method``.
+
+    Raises:
+        ValueError: If symbols is empty or no price data is available.
+    """
+    if not symbols:
+        raise ValueError("symbols must not be empty")
+
+    prices = await fetch_historical_prices(symbols, days=days)
+    if prices.empty:
+        raise ValueError("No price data available for the given symbols")
+
+    returns = _compute_returns(prices)
+    weights = _hrp_weights(returns)
+
+    return {"weights": weights, "method": "hrp"}
+
+
+async def compute_correlation(
+    symbols: list[str], days: int = 365
+) -> dict[str, Any]:
+    """Compute correlation matrix for a list of symbols.
+
+    Args:
+        symbols: List of ticker symbols (1-50).
+        days: Number of historical days to use.
+
+    Returns:
+        Dict with keys ``symbols`` (list) and ``matrix`` (list of lists).
+
+    Raises:
+        ValueError: If symbols is empty or no price data is available.
+    """
+    if not symbols:
+        raise ValueError("symbols must not be empty")
+
+    prices = await fetch_historical_prices(symbols, days=days)
+    if prices.empty:
+        raise ValueError("No price data available for the given symbols")
+
+    returns = _compute_returns(prices)
+    available = list(returns.columns)
+    corr = returns.corr().fillna(0)
+
+    matrix = corr.values.tolist()
+
+    return {"symbols": available, "matrix": matrix}
+
+
+async def compute_risk_parity(
+    symbols: list[str], days: int = 365
+) -> dict[str, Any]:
+    """Compute equal risk contribution (inverse-volatility) weights.
+
+    Args:
+        symbols: List of ticker symbols (1-50).
+        days: Number of historical days to use.
+
+    Returns:
+        Dict with keys ``weights``, ``risk_contributions``, and ``method``.
+
+    Raises:
+        ValueError: If symbols is empty or no price data is available.
+    """
+    if not symbols:
+        raise ValueError("symbols must not be empty")
+
+    prices = await fetch_historical_prices(symbols, days=days)
+    if prices.empty:
+        raise ValueError("No price data available for the given symbols")
+
+    returns = _compute_returns(prices)
+    weights = _inverse_volatility_weights(returns)
+
+    # Risk contributions: w_i * sigma_i / sum(w_j * sigma_j)
+    vols = returns.std()
+    weighted_risk = {sym: weights[sym] * float(vols[sym]) for sym in weights}
+    total_risk = sum(weighted_risk.values())
+    if total_risk > 0:
+        risk_contributions = {sym: v / total_risk for sym, v in weighted_risk.items()}
+    else:
+        n = len(weights)
+        risk_contributions = {sym: 1.0 / n for sym in weights}
+
+    return {
+        "weights": weights,
+        "risk_contributions": risk_contributions,
+        "method": "risk_parity",
+    }
diff --git a/routes_portfolio.py b/routes_portfolio.py
new file mode 100644
index 0000000..93696ff
--- /dev/null
+++ b/routes_portfolio.py
@@ -0,0 +1,54 @@
+"""Routes for portfolio optimization (HRP, correlation, risk parity)."""
+
+from fastapi import APIRouter, HTTPException
+from pydantic import BaseModel, Field
+
+from models import ApiResponse
+from route_utils import safe
+import portfolio_service
+
+router = APIRouter(prefix="/api/v1/portfolio")
+
+
+class PortfolioOptimizeRequest(BaseModel):
+    symbols: list[str] = Field(..., min_length=1, max_length=50)
+    days: int = Field(default=365, ge=1, le=3650)
+
+
+@router.post("/optimize", response_model=ApiResponse)
+@safe
+async def portfolio_optimize(request: PortfolioOptimizeRequest):
+    """Compute HRP optimal weights for a list of symbols."""
+    try:
+        result = await portfolio_service.optimize_hrp(
+            request.symbols, days=request.days
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    return ApiResponse(data=result)
+
+
+@router.post("/correlation", response_model=ApiResponse)
+@safe
+async def portfolio_correlation(request: PortfolioOptimizeRequest):
+    """Compute correlation matrix for a list of symbols."""
+    try:
+        result = await portfolio_service.compute_correlation(
+            request.symbols, days=request.days
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    return ApiResponse(data=result)
+
+
+@router.post("/risk-parity", response_model=ApiResponse)
+@safe
+async def portfolio_risk_parity(request: PortfolioOptimizeRequest):
+    """Compute equal risk contribution weights for a list of symbols."""
+    try:
+        result = await portfolio_service.compute_risk_parity(
+            request.symbols, days=request.days
+        )
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail=str(exc))
+    return ApiResponse(data=result)
diff --git a/routes_regulators.py b/routes_regulators.py
index 063b783..c43e35d 100644
--- a/routes_regulators.py
+++ b/routes_regulators.py
@@ -1,10 +1,11 @@
-"""Routes for regulatory data (CFTC, SEC)."""
+"""Routes for regulatory data (CFTC, SEC, Congress)."""
 
 from fastapi import APIRouter, Path, Query
 
 from models import ApiResponse
 from route_utils import safe, validate_symbol
 import regulators_service
+import congress_service
 
 router = APIRouter(prefix="/api/v1/regulators")
 
@@ -49,3 +50,22 @@ async def sec_cik_map(symbol: str = Path(..., min_length=1, max_length=20)):
     symbol = validate_symbol(symbol)
     data = await regulators_service.get_cik_map(symbol)
     return ApiResponse(data=data)
+
+
+# --- Congress Trading ---
+
+
+@router.get("/congress/trades", response_model=ApiResponse)
+@safe
+async def congress_trades():
+    """Recent US congress member stock trades."""
+    data = await congress_service.get_congress_trades()
+    return ApiResponse(data=data)
+
+
+@router.get("/congress/bills", response_model=ApiResponse)
+@safe
+async def congress_bills(query: str = Query(..., min_length=1, max_length=200)):
+    """Search US congress bills by keyword."""
+    data = await congress_service.search_congress_bills(query)
+    return ApiResponse(data=data)
diff --git a/tests/test_congress_service.py b/tests/test_congress_service.py
new file mode 100644
index 0000000..b4818cf
--- /dev/null
+++ b/tests/test_congress_service.py
@@ -0,0 +1,187 @@
+"""Tests for congress trading service (TDD - RED phase first)."""
+
+from unittest.mock import AsyncMock, MagicMock, patch
+
+import pytest
+
+
+# --- get_congress_trades ---
+
+
+@pytest.mark.asyncio
+async def test_get_congress_trades_happy_path():
+    """Returns list of trade dicts when OBB call succeeds."""
+    expected = [
+        {
+            "representative": "Nancy Pelosi",
+            "ticker": "NVDA",
+            "transaction_date": "2024-01-15",
+            "transaction_type": "Purchase",
+            "amount": "$1,000,001-$5,000,000",
+        }
+    ]
+
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=expected):
+        result = await congress_service.get_congress_trades()
+
+    assert isinstance(result, list)
+    assert len(result) == 1
+    assert result[0]["representative"] == "Nancy Pelosi"
+
+
+@pytest.mark.asyncio
+async def test_get_congress_trades_returns_empty_when_fn_not_available():
+    """Returns empty list when OBB congress function is not available."""
+    import congress_service
+
+    with patch.object(congress_service, "_get_congress_fn", return_value=None):
+        result = await congress_service.get_congress_trades()
+
+    assert result == []
+
+
+@pytest.mark.asyncio
+async def test_get_congress_trades_returns_empty_on_all_provider_failures():
+    """Returns empty list when all providers fail (_try_obb_call returns None)."""
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=None):
+        result = await congress_service.get_congress_trades()
+
+    assert result == []
+
+
+@pytest.mark.asyncio
+async def test_get_congress_trades_empty_list_result():
+    """Returns empty list when _try_obb_call returns empty list."""
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=[]):
+        result = await congress_service.get_congress_trades()
+
+    assert result == []
+
+
+# --- _get_congress_fn ---
+
+
+def test_get_congress_fn_returns_none_when_attribute_missing():
+    """Returns None gracefully when obb.regulators.government_us is absent."""
+    import congress_service
+
+    mock_obb = MagicMock(spec=[])  # spec with no attributes
+    with patch.object(congress_service, "obb", mock_obb):
+        result = congress_service._get_congress_fn()
+
+    assert result is None
+
+
+def test_get_congress_fn_returns_callable_when_available():
+    """Returns the congress_trading callable when attribute exists."""
+    import congress_service
+
+    mock_fn = MagicMock()
+    mock_obb = MagicMock()
+    mock_obb.regulators.government_us.congress_trading = mock_fn
+
+    with patch.object(congress_service, "obb", mock_obb):
+        result = congress_service._get_congress_fn()
+
+    assert result is mock_fn
+
+
+# --- _try_obb_call ---
+
+
+@pytest.mark.asyncio
+async def test_try_obb_call_returns_list_on_success():
+    """_try_obb_call converts OBBject result to list via to_list."""
+    import congress_service
+
+    mock_result = MagicMock()
+    expected = [{"ticker": "AAPL"}]
+
+    with patch.object(congress_service, "to_list", return_value=expected), \
+         patch("congress_service.asyncio.to_thread", new_callable=AsyncMock, return_value=mock_result):
+        result = await congress_service._try_obb_call(MagicMock())
+
+    assert result == expected
+
+
+@pytest.mark.asyncio
+async def test_try_obb_call_returns_none_on_exception():
+    """_try_obb_call returns None when asyncio.to_thread raises."""
+    import congress_service
+
+    with patch("congress_service.asyncio.to_thread", new_callable=AsyncMock, side_effect=Exception("fail")):
+        result = await congress_service._try_obb_call(MagicMock())
+
+    assert result is None
+
+
+# --- search_congress_bills ---
+
+
+@pytest.mark.asyncio
+async def test_search_congress_bills_happy_path():
+    """Returns list of bill dicts when OBB call succeeds."""
+    expected = [
+        {"title": "Infrastructure Investment and Jobs Act", "bill_id": "HR3684"},
+        {"title": "Inflation Reduction Act", "bill_id": "HR5376"},
+    ]
+
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=expected):
+        result = await congress_service.search_congress_bills("infrastructure")
+
+    assert isinstance(result, list)
+    assert len(result) == 2
+    assert result[0]["bill_id"] == "HR3684"
+
+
+@pytest.mark.asyncio
+async def test_search_congress_bills_returns_empty_when_fn_not_available():
+    """Returns empty list when OBB function is not available."""
+    import congress_service
+
+    with patch.object(congress_service, "_get_congress_fn", return_value=None):
+        result = await congress_service.search_congress_bills("taxes")
+
+    assert result == []
+
+
+@pytest.mark.asyncio
+async def test_search_congress_bills_returns_empty_on_failure():
+    """Returns empty list when all providers fail."""
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=None):
+        result = await congress_service.search_congress_bills("taxes")
+
+    assert result == []
+
+
+@pytest.mark.asyncio
+async def test_search_congress_bills_empty_results():
+    """Returns empty list when _try_obb_call returns empty list."""
+    import congress_service
+
+    mock_fn = MagicMock()
+    with patch.object(congress_service, "_get_congress_fn", return_value=mock_fn), \
+         patch.object(congress_service, "_try_obb_call", new_callable=AsyncMock, return_value=[]):
+        result = await congress_service.search_congress_bills("nonexistent")
+
+    assert result == []
diff --git a/tests/test_portfolio_service.py b/tests/test_portfolio_service.py
new file mode 100644
index 0000000..d98b2bb
--- /dev/null
+++ b/tests/test_portfolio_service.py
@@ -0,0 +1,263 @@
+"""Tests for portfolio optimization service (TDD - RED phase first)."""
+
+from unittest.mock import AsyncMock, patch
+
+import pytest
+
+
+# --- HRP Optimization ---
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_hrp_optimize_happy_path(mock_fetch):
+    """HRP returns weights that sum to ~1.0 for valid symbols."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {
+            "AAPL": [150.0, 151.0, 149.0, 152.0, 153.0],
+            "MSFT": [300.0, 302.0, 298.0, 305.0, 307.0],
+            "GOOGL": [2800.0, 2820.0, 2790.0, 2830.0, 2850.0],
+        }
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.optimize_hrp(
+        ["AAPL", "MSFT", "GOOGL"], days=365
+    )
+
+    assert result["method"] == "hrp"
+    assert set(result["weights"].keys()) == {"AAPL", "MSFT", "GOOGL"}
+    total = sum(result["weights"].values())
+    assert abs(total - 1.0) < 0.01
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_hrp_optimize_single_symbol(mock_fetch):
+    """Single symbol gets weight of 1.0."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {"AAPL": [150.0, 151.0, 149.0, 152.0, 153.0]}
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.optimize_hrp(["AAPL"], days=365)
+
+    assert result["weights"]["AAPL"] == pytest.approx(1.0, abs=0.01)
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_hrp_optimize_no_data_raises(mock_fetch):
+    """Raises ValueError when no price data is available."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame()
+
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="No price data"):
+        await portfolio_service.optimize_hrp(["AAPL", "MSFT"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_hrp_optimize_empty_symbols_raises():
+    """Raises ValueError for empty symbol list."""
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="symbols"):
+        await portfolio_service.optimize_hrp([], days=365)
+
+
+# --- Correlation Matrix ---
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_correlation_matrix_happy_path(mock_fetch):
+    """Correlation matrix has 1.0 on diagonal and valid shape."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {
+            "AAPL": [150.0, 151.0, 149.0, 152.0, 153.0],
+            "MSFT": [300.0, 302.0, 298.0, 305.0, 307.0],
+            "GOOGL": [2800.0, 2820.0, 2790.0, 2830.0, 2850.0],
+        }
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.compute_correlation(
+        ["AAPL", "MSFT", "GOOGL"], days=365
+    )
+
+    assert result["symbols"] == ["AAPL", "MSFT", "GOOGL"]
+    matrix = result["matrix"]
+    assert len(matrix) == 3
+    assert len(matrix[0]) == 3
+    # Diagonal should be 1.0
+    for i in range(3):
+        assert abs(matrix[i][i] - 1.0) < 0.01
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_correlation_matrix_two_symbols(mock_fetch):
+    """Two-symbol correlation is symmetric."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {
+            "AAPL": [150.0, 151.0, 149.0, 152.0, 153.0],
+            "MSFT": [300.0, 302.0, 298.0, 305.0, 307.0],
+        }
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.compute_correlation(["AAPL", "MSFT"], days=365)
+
+    matrix = result["matrix"]
+    # Symmetric: matrix[0][1] == matrix[1][0]
+    assert abs(matrix[0][1] - matrix[1][0]) < 0.001
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_correlation_no_data_raises(mock_fetch):
+    """Raises ValueError when no data is returned."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame()
+
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="No price data"):
+        await portfolio_service.compute_correlation(["AAPL", "MSFT"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_correlation_empty_symbols_raises():
+    """Raises ValueError for empty symbol list."""
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="symbols"):
+        await portfolio_service.compute_correlation([], days=365)
+
+
+# --- Risk Parity ---
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_risk_parity_happy_path(mock_fetch):
+    """Risk parity returns weights and risk_contributions summing to ~1.0."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {
+            "AAPL": [150.0, 151.0, 149.0, 152.0, 153.0],
+            "MSFT": [300.0, 302.0, 298.0, 305.0, 307.0],
+            "GOOGL": [2800.0, 2820.0, 2790.0, 2830.0, 2850.0],
+        }
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.compute_risk_parity(
+        ["AAPL", "MSFT", "GOOGL"], days=365
+    )
+
+    assert result["method"] == "risk_parity"
+    assert set(result["weights"].keys()) == {"AAPL", "MSFT", "GOOGL"}
+    assert set(result["risk_contributions"].keys()) == {"AAPL", "MSFT", "GOOGL"}
+    total_w = sum(result["weights"].values())
+    assert abs(total_w - 1.0) < 0.01
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_risk_parity_single_symbol(mock_fetch):
+    """Single symbol gets weight 1.0 and risk_contribution 1.0."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame(
+        {"AAPL": [150.0, 151.0, 149.0, 152.0, 153.0]}
+    )
+
+    import portfolio_service
+
+    result = await portfolio_service.compute_risk_parity(["AAPL"], days=365)
+
+    assert result["weights"]["AAPL"] == pytest.approx(1.0, abs=0.01)
+    assert result["risk_contributions"]["AAPL"] == pytest.approx(1.0, abs=0.01)
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical_prices", new_callable=AsyncMock)
+async def test_risk_parity_no_data_raises(mock_fetch):
+    """Raises ValueError when no price data is available."""
+    import pandas as pd
+
+    mock_fetch.return_value = pd.DataFrame()
+
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="No price data"):
+        await portfolio_service.compute_risk_parity(["AAPL", "MSFT"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_risk_parity_empty_symbols_raises():
+    """Raises ValueError for empty symbol list."""
+    import portfolio_service
+
+    with pytest.raises(ValueError, match="symbols"):
+        await portfolio_service.compute_risk_parity([], days=365)
+
+
+# --- fetch_historical_prices helper ---
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical")
+async def test_fetch_historical_prices_returns_dataframe(mock_fetch_hist):
+    """fetch_historical_prices assembles a price DataFrame from OBBject results."""
+    import pandas as pd
+    from unittest.mock import MagicMock
+
+    mock_result = MagicMock()
+    mock_result.results = [
+        MagicMock(date="2024-01-01", close=150.0),
+        MagicMock(date="2024-01-02", close=151.0),
+    ]
+    mock_fetch_hist.return_value = mock_result
+
+    import portfolio_service
+
+    df = await portfolio_service.fetch_historical_prices(["AAPL"], days=30)
+
+    assert isinstance(df, pd.DataFrame)
+    assert "AAPL" in df.columns
+
+
+@pytest.mark.asyncio
+@patch("portfolio_service.fetch_historical")
+async def test_fetch_historical_prices_skips_none(mock_fetch_hist):
+    """fetch_historical_prices returns empty DataFrame when all fetches fail."""
+    import pandas as pd
+
+    mock_fetch_hist.return_value = None
+
+    import portfolio_service
+
+    df = await portfolio_service.fetch_historical_prices(["AAPL", "MSFT"], days=30)
+
+    assert isinstance(df, pd.DataFrame)
+    assert df.empty
diff --git a/tests/test_routes_congress.py b/tests/test_routes_congress.py
new file mode 100644
index 0000000..5fb75eb
--- /dev/null
+++ b/tests/test_routes_congress.py
@@ -0,0 +1,98 @@
+"""Tests for congress trading routes (TDD - RED phase first)."""
+
+from unittest.mock import patch, AsyncMock
+
+import pytest
+from httpx import AsyncClient, ASGITransport
+
+from main import app
+
+
+@pytest.fixture
+async def client():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as c:
+        yield c
+
+
+# --- GET /api/v1/regulators/congress/trades ---
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.get_congress_trades", new_callable=AsyncMock)
+async def test_congress_trades_happy_path(mock_fn, client):
+    mock_fn.return_value = [
+        {
+            "representative": "Nancy Pelosi",
+            "ticker": "NVDA",
+            "transaction_date": "2024-01-15",
+            "transaction_type": "Purchase",
+            "amount": "$1,000,001-$5,000,000",
+        }
+    ]
+    resp = await client.get("/api/v1/regulators/congress/trades")
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["success"] is True
+    assert len(data["data"]) == 1
+    assert data["data"][0]["representative"] == "Nancy Pelosi"
+    mock_fn.assert_called_once()
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.get_congress_trades", new_callable=AsyncMock)
+async def test_congress_trades_empty(mock_fn, client):
+    mock_fn.return_value = []
+    resp = await client.get("/api/v1/regulators/congress/trades")
+    assert resp.status_code == 200
+    assert resp.json()["data"] == []
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.get_congress_trades", new_callable=AsyncMock)
+async def test_congress_trades_service_error_returns_502(mock_fn, client):
+    mock_fn.side_effect = RuntimeError("Data provider unavailable")
+    resp = await client.get("/api/v1/regulators/congress/trades")
+    assert resp.status_code == 502
+
+
+# --- GET /api/v1/regulators/congress/bills ---
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.search_congress_bills", new_callable=AsyncMock)
+async def test_congress_bills_happy_path(mock_fn, client):
+    mock_fn.return_value = [
+        {"title": "Infrastructure Investment and Jobs Act", "bill_id": "HR3684"},
+        {"title": "Inflation Reduction Act", "bill_id": "HR5376"},
+    ]
+    resp = await client.get("/api/v1/regulators/congress/bills?query=infrastructure")
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["success"] is True
+    assert len(data["data"]) == 2
+    assert data["data"][0]["bill_id"] == "HR3684"
+    mock_fn.assert_called_once_with("infrastructure")
+
+
+@pytest.mark.asyncio
+async def test_congress_bills_missing_query(client):
+    resp = await client.get("/api/v1/regulators/congress/bills")
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.search_congress_bills", new_callable=AsyncMock)
+async def test_congress_bills_empty(mock_fn, client):
+    mock_fn.return_value = []
+    resp = await client.get("/api/v1/regulators/congress/bills?query=nonexistent")
+    assert resp.status_code == 200
+    assert resp.json()["data"] == []
+
+
+@pytest.mark.asyncio
+@patch("routes_regulators.congress_service.search_congress_bills", new_callable=AsyncMock)
+async def test_congress_bills_service_error_returns_502(mock_fn, client):
+    mock_fn.side_effect = RuntimeError("Congress API unavailable")
+    resp = await client.get("/api/v1/regulators/congress/bills?query=tax")
+    assert resp.status_code == 502
diff --git a/tests/test_routes_portfolio.py b/tests/test_routes_portfolio.py
new file mode 100644
index 0000000..7b8db66
--- /dev/null
+++ b/tests/test_routes_portfolio.py
@@ -0,0 +1,225 @@
+"""Tests for portfolio optimization routes (TDD - RED phase first)."""
+
+from unittest.mock import patch, AsyncMock
+
+import pytest
+from httpx import AsyncClient, ASGITransport
+
+from main import app
+
+
+@pytest.fixture
+async def client():
+    transport = ASGITransport(app=app)
+    async with AsyncClient(transport=transport, base_url="http://test") as c:
+        yield c
+
+
+# --- POST /api/v1/portfolio/optimize ---
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.optimize_hrp", new_callable=AsyncMock)
+async def test_portfolio_optimize_happy_path(mock_fn, client):
+    mock_fn.return_value = {
+        "weights": {"AAPL": 0.35, "MSFT": 0.32, "GOOGL": 0.33},
+        "method": "hrp",
+    }
+    resp = await client.post(
+        "/api/v1/portfolio/optimize",
+        json={"symbols": ["AAPL", "MSFT", "GOOGL"], "days": 365},
+    )
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["success"] is True
+    assert data["data"]["method"] == "hrp"
+    assert "AAPL" in data["data"]["weights"]
+    mock_fn.assert_called_once_with(["AAPL", "MSFT", "GOOGL"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_portfolio_optimize_missing_symbols(client):
+    resp = await client.post("/api/v1/portfolio/optimize", json={"days": 365})
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_portfolio_optimize_empty_symbols(client):
+    resp = await client.post(
+        "/api/v1/portfolio/optimize", json={"symbols": [], "days": 365}
+    )
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_portfolio_optimize_too_many_symbols(client):
+    symbols = [f"SYM{i}" for i in range(51)]
+    resp = await client.post(
+        "/api/v1/portfolio/optimize", json={"symbols": symbols, "days": 365}
+    )
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.optimize_hrp", new_callable=AsyncMock)
+async def test_portfolio_optimize_service_error_returns_502(mock_fn, client):
+    mock_fn.side_effect = RuntimeError("Computation failed")
+    resp = await client.post(
+        "/api/v1/portfolio/optimize",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 502
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.optimize_hrp", new_callable=AsyncMock)
+async def test_portfolio_optimize_value_error_returns_400(mock_fn, client):
+    mock_fn.side_effect = ValueError("No price data available")
+    resp = await client.post(
+        "/api/v1/portfolio/optimize",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 400
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.optimize_hrp", new_callable=AsyncMock)
+async def test_portfolio_optimize_default_days(mock_fn, client):
+    mock_fn.return_value = {"weights": {"AAPL": 1.0}, "method": "hrp"}
+    resp = await client.post(
+        "/api/v1/portfolio/optimize", json={"symbols": ["AAPL"]}
+    )
+    assert resp.status_code == 200
+    mock_fn.assert_called_once_with(["AAPL"], days=365)
+
+
+# --- POST /api/v1/portfolio/correlation ---
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_correlation", new_callable=AsyncMock)
+async def test_portfolio_correlation_happy_path(mock_fn, client):
+    mock_fn.return_value = {
+        "symbols": ["AAPL", "MSFT"],
+        "matrix": [[1.0, 0.85], [0.85, 1.0]],
+    }
+    resp = await client.post(
+        "/api/v1/portfolio/correlation",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["success"] is True
+    assert data["data"]["symbols"] == ["AAPL", "MSFT"]
+    assert data["data"]["matrix"][0][0] == pytest.approx(1.0)
+    mock_fn.assert_called_once_with(["AAPL", "MSFT"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_portfolio_correlation_missing_symbols(client):
+    resp = await client.post("/api/v1/portfolio/correlation", json={"days": 365})
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_portfolio_correlation_empty_symbols(client):
+    resp = await client.post(
+        "/api/v1/portfolio/correlation", json={"symbols": [], "days": 365}
+    )
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_correlation", new_callable=AsyncMock)
+async def test_portfolio_correlation_service_error_returns_502(mock_fn, client):
+    mock_fn.side_effect = RuntimeError("Failed")
+    resp = await client.post(
+        "/api/v1/portfolio/correlation",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 502
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_correlation", new_callable=AsyncMock)
+async def test_portfolio_correlation_value_error_returns_400(mock_fn, client):
+    mock_fn.side_effect = ValueError("No price data available")
+    resp = await client.post(
+        "/api/v1/portfolio/correlation",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 400
+
+
+# --- POST /api/v1/portfolio/risk-parity ---
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_risk_parity", new_callable=AsyncMock)
+async def test_portfolio_risk_parity_happy_path(mock_fn, client):
+    mock_fn.return_value = {
+        "weights": {"AAPL": 0.35, "MSFT": 0.33, "GOOGL": 0.32},
+        "risk_contributions": {"AAPL": 0.34, "MSFT": 0.33, "GOOGL": 0.33},
+        "method": "risk_parity",
+    }
+    resp = await client.post(
+        "/api/v1/portfolio/risk-parity",
+        json={"symbols": ["AAPL", "MSFT", "GOOGL"], "days": 365},
+    )
+    assert resp.status_code == 200
+    data = resp.json()
+    assert data["success"] is True
+    assert data["data"]["method"] == "risk_parity"
+    assert "risk_contributions" in data["data"]
+    mock_fn.assert_called_once_with(["AAPL", "MSFT", "GOOGL"], days=365)
+
+
+@pytest.mark.asyncio
+async def test_portfolio_risk_parity_missing_symbols(client):
+    resp = await client.post("/api/v1/portfolio/risk-parity", json={"days": 365})
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+async def test_portfolio_risk_parity_empty_symbols(client):
+    resp = await client.post(
+        "/api/v1/portfolio/risk-parity", json={"symbols": [], "days": 365}
+    )
+    assert resp.status_code == 422
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_risk_parity", new_callable=AsyncMock)
+async def test_portfolio_risk_parity_service_error_returns_502(mock_fn, client):
+    mock_fn.side_effect = RuntimeError("Failed")
+    resp = await client.post(
+        "/api/v1/portfolio/risk-parity",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 502
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_risk_parity", new_callable=AsyncMock)
+async def test_portfolio_risk_parity_value_error_returns_400(mock_fn, client):
+    mock_fn.side_effect = ValueError("No price data available")
+    resp = await client.post(
+        "/api/v1/portfolio/risk-parity",
+        json={"symbols": ["AAPL", "MSFT"], "days": 365},
+    )
+    assert resp.status_code == 400
+
+
+@pytest.mark.asyncio
+@patch("routes_portfolio.portfolio_service.compute_risk_parity", new_callable=AsyncMock)
+async def test_portfolio_risk_parity_default_days(mock_fn, client):
+    mock_fn.return_value = {
+        "weights": {"AAPL": 1.0},
+        "risk_contributions": {"AAPL": 1.0},
+        "method": "risk_parity",
+    }
+    resp = await client.post(
+        "/api/v1/portfolio/risk-parity", json={"symbols": ["AAPL"]}
+    )
+    assert resp.status_code == 200
+    mock_fn.assert_called_once_with(["AAPL"], days=365)