Debt-Equity Spread in Equities

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Quant Buffet native backtest IDE

Edit and run Quant Buffet Python for Debt-Equity Spread in Equities in the browser. Results update live with equity, drawdown, and metrics charts. Allowed: backtest.data, backtest.engine, backtest.metrics, numpy, pandas. Define ASSETS and make_on_day(prices). Shortcut: Ctrl+Enter. API docs →

Ready — edit code, then Run backtest.
IDE · 43 lines
Quant Buffet syntax cheat sheet (copy / insert)

Paste these fragments into the editor. The sandbox rejects QuantConnect, os, and network libraries.

Required imports
Only these libraries are allowed in the sandbox.
from __future__ import annotations

import numpy as np
import pandas as pd

from backtest.data import load_daily_prices
from backtest.engine import EngineConfig, PortfolioEngine
from backtest.metrics import compute_metrics
ASSETS list (whitelisted ETFs)
Module-level list. Tickers must be in the Quant Buffet whitelist.
ASSETS = ["SPY", "QQQ", "TLT", "GLD", "BIL"]
make_on_day contract
Must return (on_day, ready). on_day calls engine.set_target_weights.
def make_on_day(prices: pd.DataFrame):
    cols = [c for c in ASSETS if c in prices.columns]
    sma = prices[cols].rolling(200, min_periods=200).mean()
    state = {"last": None}

    def on_day(engine: PortfolioEngine, dt: pd.Timestamp) -> None:
        if sma.loc[dt].isna().all():
            return
        key = (dt.year, dt.month)
        if state["last"] == key:
            return
        state["last"] = key
        long = [
            s for s in cols
            if pd.notna(prices.at[dt, s]) and pd.notna(sma.at[dt, s])
            and prices.at[dt, s] > sma.at[dt, s]
        ]
        weights = {} if not long else {s: 1.0 / len(long) for s in long}
        engine.set_target_weights(dt, weights)

    ready = sma.dropna(how="all").index.min() if sma.notna().any().any() else None
    return on_day, ready
Set target weights
Weights should sum to about 1.0. Empty dict = 100% cash.
engine.set_target_weights(dt, {"SPY": 0.60, "BIL": 0.40})

Live backtest performance

CAGR
3.47%
Sharpe
0.73
Max DD
-15.90%
Vol
4.84%
Sortino
1.12
Beta
0.11

Run the backtest to populate charts.

Export to your platform

Transform Quant Buffet lab code (ASSETS + make_on_day / PortfolioEngine) into native classes for a third-party IDE — then copy and paste.

Run in: QuantConnect Cloud or LEAN CLI · QCAlgorithm with Equity securities and monthly rebalance.

Detected pattern: Custom / hybridAssets: SPY, TLT, GLD, BIL
# Generated from Quant Buffet → QuantConnect LEAN
# Strategy: Debt-Equity Spread in Equities
# Detected pattern: Custom / hybrid
# Source uses Quant Buffet lab APIs (ASSETS + make_on_day / PortfolioEngine).
# Review fees, data, and risk before live trading — educational export only.

from AlgorithmImports import *


class QuantBuffetExport(QCAlgorithm):
    def Initialize(self):
        self.SetStartDate(2010, 1, 1)
        self.SetCash(100000)
        tickers = ["SPY", "TLT", "GLD", "BIL"]
        self.symbols = []
        for t in tickers:
            if "-" in t:  # crypto proxy e.g. BTC-USD
                self.symbols.append(self.AddCrypto(t.replace("-USD", ""), Resolution.Daily).Symbol)
            else:
                self.symbols.append(self.AddEquity(t, Resolution.Daily).Symbol)
        self.Schedule.On(
            self.DateRules.MonthStart(self.symbols[0]),
            self.TimeRules.AfterMarketOpen(self.symbols[0], 30),
            self.Rebalance,
        )
        # Logic: Custom Quant Buffet logic — adapt the signal block to match your lab on_day().

    def Rebalance(self):
        # Pattern: custom — Custom Quant Buffet logic — adapt the signal block to match your lab on_day().
        # Default: equal-weight. Port your make_on_day weights here via SetHoldings.
        w = 1.0 / len(self.symbols) if self.symbols else 0.0
        for symbol in self.symbols:
            self.SetHoldings(symbol, w)

Exported code uses the platform’s native classes and libraries. Install dependencies in your third-party IDE, then run. Validate before live trading.

Academic paper

The Debt-Equity Spread

AuthorsHui Chen; Zhiyao Chen; Jun Li

Institute
  • Massachusetts Institute of Technology
  • National Bureau of Economic Research
  • ?National Bureau of Economic Research (NBER)
  • Chinese University of Hong Kong
  • ?The Chinese University of Hong Kong (CUHK) - Department of Finance
  • ?University of Texas at Dallas

Screenshot from the original paper

Screenshot from the original paper
Screenshot from the original paper

Strategy in a nutshell

The strategy targets common stocks listed on NYSE, AMEX, and NASDAQ, excluding financial firms. Stock and accounting data are obtained from CRSP and Compustat, with bond returns from Lehman Brothers Fixed Income Database, NAIC, and WRDS. Using the zero-coupon yield curve from FRED, the strategy calculates the debt-equity spread as the difference between the actual credit spread and the equity-implied credit spread. Stocks are sorted monthly into quintiles based on their debt-equity spread, going long on the bottom quintile (low spread) and short on the top quintile (high spread). Portfolios are value-weighted and rebalanced monthly.

Economic rationale

The debt-equity spread identifies mispricing between equity and bonds by capturing valuation gaps. A high spread indicates overvalued equity and undervalued bonds, while a low spread indicates the opposite. The anomaly persists despite standard risk factors, firm characteristics, or security traits, as corporate actions and insider behaviors often exploit these mispricings. Executives tend to sell high spread stocks more frequently, highlighting the strategy’s ability to systematically capitalize on persistent misvaluation in both equity and bond markets.

Backtest performance

Annualised return3.47%
Volatility4.84%
Beta0.11
Sharpe ratio0.73
Sortino ratio1.12
Maximum drawdown-15.90%