Debt-Equity Spread in Bonds

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Quant Buffet native backtest IDE

Edit and run Quant Buffet Python for Debt-Equity Spread in Bonds 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 →

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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 Bonds
# 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

This strategy trades corporate bonds of non-financial firms listed on NYSE, AMEX, and NASDAQ. Using CRSP and Compustat for equity and accounting data, and Lehman Brothers Fixed Income Database, NAIC, and WRDS for bond data, the debt-equity spread is calculated as the difference between the actual credit spread and the equity-implied credit spread. The latter is derived from theoretical bond prices and matched Treasury yields. Each month, bonds are sorted into quintiles by their firm’s debt-equity spread. The portfolio goes long the highest quintile and short the lowest, with monthly rebalancing and value-weighted positions.

Economic rationale

The debt-equity spread identifies relative mispricing between bonds and equities. A high spread signals overvalued equity and undervalued bonds, while a low spread indicates the opposite. This anomaly persists as firms and insiders exploit mispricing via equity issuance and debt retirement, and executives tend to sell overvalued stock. The effect is robust to standard risk factors, firm characteristics, and demonstrates systematic, persistent mispricing exploitable through this strategy.

Backtest performance

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