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Behind the numbers.

Code examples, market analysis, and data quality deep-dives.

How to Get Historical Market Cap Data in Python
How Much of the S&P 500 Survives 20 Years? Index Turnover Analysis in Python
Does Joining the S&P 500 Bring New Institutional Owners? 13F Event Study in Python
Is Volatility Seasonal? Calendar Month Analysis of Realized Volatility in Python
Does Fast Revenue Growth Force Companies to Borrow? Cash Funding Analysis in Python
How Far Back Does SEC EDGAR Data Go?
Are One-Time Charges Really One-Time? Charge Frequency Analysis in Python
Does Buying the Dip Work? Short-Term Reversal by Volatility Regime in Python
Alpha Vantage vs Massive vs xfinlink for Fundamentals
How Long Does a Stock Take to Recover From a 50% Fall? Drawdown Analysis in Python
Do Companies That Shrink Their Share Count Outperform? Net Buyback Yield in Python
How Much Does the Dow's Price Weighting Distort It? Index Weighting Analysis in Python
How to Get SEC Form 4 Insider Trading Data in Python
Can Anything Predict Next Month's Stock Returns? Out-of-Sample R-Squared Testing in Python
How Much of a Stock's Return Comes From Its Sector? Variance Decomposition in Python
Altman Z-Score: Where To Get It in Python
Do Value Screens Agree on Which Stocks Are Cheap? Multiple Overlap Analysis in Python
Annual vs Quarterly Financial Data: Which to Use
Do High Returns on Capital Persist? ROIC Fade Analysis in Python
Does Past Beta Predict Future Beta? Beta Stability Testing in Python
Do Defensive Sectors Actually Defend? Up and Down Capture in Python
How to Choose a Financial Data API
Do Small Caps Actually Beat Large Caps? Size Premium Test in Python
What If You Miss the Market's Best Days? Extreme-Day Analysis in Python
Does Rebalancing Add Return? Fixed-Weight vs Drift Portfolios in Python
Which S&P 500 Companies Are Closest to Default? Merton Distance-to-Default in Python
What Happens to Stocks Removed From the S&P 500? Replacement Pair Analysis in Python
Does the Golden Cross Work? 50/200 Moving Average Crossover Backtest in Python
Financial Data for Academic Finance Research
Does Skipping the Most Recent Month Improve Momentum? S&P 500 Decile Sorts in Python
Does Cointegration Survive Out of Sample? Pairs Trading Validation in Python
Which Dividends Are Not Covered by Cash? Free-Cash-Flow Coverage Screening in Python
GICS vs SIC vs NAICS: Which Industry Classification to Use
How Many Stocks Does It Take to Diversify? Random Portfolio Simulation in Python
How Many Days of Data Does a Volatility Estimate Need? Range-Based Estimators in Python
How Much of S&P 500 Cash Flow Is Stock Compensation? Cross-Sectional Analysis in Python
What Is a 13F Filing? Institutional Holdings Explained
Does Revenue Growth Explain Profit Growth? Cross-Sectional Decomposition in Python
How Much of the Nasdaq 100 Is Already in the S&P 500? Index Overlap Analysis in Python
How Often Does a 99% Value-at-Risk Limit Actually Break? VaR Backtesting in Python
Real-Time vs End-of-Day Market Data: Which Do You Need?
How Concentrated Are S&P 500 Earnings? Point-in-Time Index Analysis in Python
Does Volatility Scale With the Square Root of Time? Variance Ratio Test in Python
Does Goodwill Distort the Price-to-Book Screen? Goodwill-Adjusted Valuation in Python
How Are Shares Outstanding Reported (and Why They Disagree)
Do Low-Volatility Stocks Deliver Better Risk-Adjusted Returns? S&P 500 Quintile Sorts in Python
Does Trend Following Beat Buy and Hold? Time-Series Momentum in Python
Has the Stock-Bond Correlation Flipped? 60/40 Portfolio Risk in Python
What API to Use for a Stock Screener
Which Assets Hedge Inflation Shocks? Macro Factor Betas in Python
Does Covariance Shrinkage Beat the Sample Covariance? Minimum-Variance Portfolios in Python
Do Faster Inventory Turns Mean Thinner Margins? Gross Margin Return on Inventory in Python
SEC EDGAR API vs Fundamentals API: Which to Use
Does Fast Earnings Growth Persist? Rank Correlation Analysis in Python
Split Adjustment Explained: Adjusted Close vs Close
Which Trading Day of the Month Pays Best? Turn-of-the-Month Analysis in Python
Can You Use Yahoo Finance Data Commercially?
How Many Independent Bets Does a Nine-Sector Portfolio Give You? Eigenvalue Analysis in Python
Which Volatility Forecast Wins One Month Ahead? HAR vs EWMA in Python
How Concentrated Are Institutional Equity Portfolios? Form 13F Concentration Analysis in Python
Do Stocks Earn Their Returns Overnight or Intraday? Return Decomposition in Python
When Do Corporate Insiders Actually Trade? Form 4 Timing Analysis in Python
Data Requirements for Backtesting a Trading Strategy
What Is Survivorship Bias in Backtesting?
Do High Dividend Yields Come From Bigger Payouts or Falling Prices? Yield Decomposition in Python
Do Stocks Fall Harder Than They Rise? Downside Beta vs Upside Beta in Python
Does Volatility Targeting Improve Sharpe Ratios? Seven-Asset Backtest in Python
Free Stock Market Data APIs: What You Actually Get
How to Give an LLM Financial Data With an MCP Server
Does Post-Earnings Announcement Drift Survive Real Filing Dates? PEAD Event Study in Python
Do Insider Buying Clusters Predict Returns? Signal Testing in Python
Does the S&P 500 Index Effect Still Exist? Event Study in Python
Are Companies Leaving the S&P 500 Faster Than They Used To? Index Survival Analysis in Python
Does Gross Profitability Predict Stock Returns? Quintile Factor Test in Python
What Growth Rate Is the Market Pricing In? Reverse DCF in Python
Does a Strong Balance Sheet Cushion Drawdowns? Leverage and Downside Risk in Python
Does Ticker Recycling Corrupt a Mean-Reversion Backtest? Entity-Resolved Z-Scores in Python
How Much of a Growth Screen's Backtested Edge Is Survivorship Bias? Point-in-Time Index Testing in Python
Why Do Leveraged ETFs Decay? Measuring Volatility Drag in Python
Are Consumer Staples Margins Shrinking Under Inflation? Gross Margin Trend Analysis in Python
Do Weak Jobs Reports Predict Market Drawdowns? NFP Surprise Event Study in Python
Is the Rotation From Tech to Industrials Backed by Earnings? Relative EPS Growth Analysis in Python
Is the Semiconductor Rally Broadening Beyond NVIDIA? Return Dispersion Analysis in Python
Which Stocks Benefit Most When Oil Prices Fall? Oil Beta Screening in Python
Do Bond Returns Predict Stock Returns? Granger Causality Test in Python
Which Stocks Actually Drive Portfolio Returns? Shapley Value Attribution in Python
Does "Sell in May" Still Work? Calendar Anomaly Backtest in Python
How to Build Complete Price History Through Ticker Changes? Entity Resolution in Python
Are KO and PEP Cointegrated? Pairs Trading Signal Construction in Python
Which Commodities Have the Strongest Momentum? Rotation Backtest in Python
Which Commodity ETFs Have the Worst Tail Risk? Expected Shortfall in Python
Are Gold Miners Leveraged Gold Bets? Rolling Beta Analysis in Python
Does the Base-Metals-to-Gold Ratio Lead Cyclical Stocks? Signal Test in Python
Can Risk Parity Tame Commodity Volatility? Portfolio Optimization in Python
Are Power Stocks Becoming an AI Infrastructure Trade? Momentum Screening in Python
Which AI Chip Stocks Have Margin Momentum? Profitability Trend Analysis in Python
Which AI Stocks Are Cheapest Relative to Growth? Growth-Adjusted Valuation in Python
Does AI Stock Leadership Persist? Momentum Backtest in Python
Which AI Stocks Have the Cleanest Balance Sheets? Net Cash Screening in Python
Can Risk Parity Reduce Mega-Cap Drawdowns? Portfolio Optimization in Python
Which Growth Stocks Are Self-Funding? Cash-Flow Quality Screening in Python
Which Sectors Struggle When the Dollar Rallies? Sector Rotation Analysis in Python
Do Cheap Stocks Hold Up When Bonds Sell Off? Valuation Rotation in Python
Does the Nasdaq 100 Have Better Growth Quality Than the Dow? Index Constituent Analysis in Python
Do Healthcare Cash-Flow Margins Predict Returns? Signal Evaluation in Python
Which Dividend Stocks Survive a Cash-Flow Stress Test? Dividend Screening in Python
Does Heavy Insider Selling Predict Weak Returns? Insider Flow Test in Python
Can Quality Screens Reduce Small-Cap Balance-Sheet Risk? Russell 2000 Test in Python
Which Retailers Have Positive Operating Leverage? Margin Screening in Python
Is MSTR a Leveraged Bitcoin Proxy? Rolling Beta Analysis in Python
Is Micron's Memory Cycle Recovering? Inventory and Margin Forecasting in Python
Which Sectors Work When Bonds Rally? Rate-Sensitive Rotation in Python
Do One-Month Price Extremes Reverse? Signal Evaluation in Python
Do Low-Volatility S&P 500 Stocks Reduce Drawdowns? Factor Test in Python
Is AI Capex Paying Back Fast Enough? Revenue Hurdle Forecasting in Python
Could Shorter AI Asset Lives Hit Earnings? Depreciation Stress Test in Python
How Much AI Capex Risk Can a Portfolio Remove? Constrained Optimization in Python
Is the AI Capex Trade Crowded? Rolling Volatility and Sector Rotation in Python
Did the AI Boom Come From Existing S&P 500 Members? Point-in-Time Momentum Test in Python
Is AI Revenue Circular? Customer-Vendor Capex Loop Analysis in Python
Is the AI Trade Connected to Private Credit? Rolling Correlation Network in Python
Is Apollo More Balance-Sheet Sensitive Than Peers? Leverage Screen in Python
Are AI Earnings Supported by Cash Flow? Accrual and Capex Screen in Python
Can Defensive Stocks Hedge AI Drawdowns? Basket Regime Test in Python
How Fast Does the Market Price In Fed Decisions? FOMC Event Study in Python
How Much Are Options Sellers Overpaid? The Variance Risk Premium in Python
Which Companies Have the Worst Earnings Quality? Sloan Accrual Screen with Geographic Revenue Data in Python
Does the Oil-to-Gold Ratio Signal Recessions? XLE/GLD Backtest in Python
Is AI Spending Crowding Out Free Cash Flow? Capex Sustainability Across the Mag 7 in Python
Does a Long Energy / Short Bonds Portfolio Capture Inflation Surprises? Factor Construction in Python
Can a Hidden Markov Model Detect Oil Market Regimes? HMM Analysis in Python
Do Grain Prices Predict Food Inflation? Granger Causality Test in Python
Does the Corporate Credit Spread Predict Stock Market Crashes? BAA-AAA Spread Analysis in Python
Do Oil Stocks Hedge Inflation? Rolling Beta Analysis in Python
Which Stocks Are Most Rate-Sensitive? Equity Duration via Bond Beta in Python
Which Companies Have the Highest Accrual Ratios? Earnings Quality Screening in Python
Is Alpha Persistent or Decaying? Rolling Sharpe Ratio Analysis in Python
Are Markets Trending or Mean-Reverting? Hurst Exponent Analysis in Python
Is Consumer Discretionary vs Staples a Leading Indicator? XLY/XLP Ratio Analysis in Python
Does Heavy Capex Predict Future Stock Returns? Capital Expenditure Analysis in Python
How to Estimate Cost of Equity Using CAPM in Python
Is Volatility Predictable? Testing for Volatility Clustering in Python
Which Industrials Are Overleveraged? Net Debt to EBITDA Screening in Python
GM Before and After Bankruptcy: Why Entity Resolution Matters for Financial Data
What Is Adjusted Beta? Merrill Lynch Beta Shrinkage in Python
How Good Is a Stock Pick? Information Ratio and Tracking Error in Python
Do Stock Returns Follow a Normal Distribution? Testing for Fat Tails in Python
Which Large Caps Have the Highest Free Cash Flow Yield? FCF Screening in Python
Which Sectors Won Over 5 Years? Sector Rotation Analysis in Python
How to Forecast Stock Volatility with GARCH Models in Python
Are Stock Prices Mean-Reverting? Augmented Dickey-Fuller Test in Python
How to Calculate CAPM Alpha and Beta with Regression in Python
How to Compare Sector Sharpe Ratios and Sortino Ratios in Python
DELL: Why Stitching Historical Price Data Together Is Wrong
How to Analyze Drawdown and Recovery for Bank Stocks in Python
How to Screen SaaS Stocks by Revenue Growth and Cash Flow in Python
How to Screen REITs by Dividend Yield and Valuation in Python
How Correlated Are the Magnificent 7? Intra-Group Correlation in Python
AAPL vs XOM: Do Individual Stocks Have Seasonal Patterns?
How to Rank Large-Cap Stocks by Momentum in Python
How to Build a Multi-Endpoint Financial Dashboard in Python
How to Compare Volatility Across Energy Stocks in Python
How to Screen Healthcare Stocks by Valuation in Python
How to Build a Sector Correlation Matrix for Portfolio Diversification in Python
How to Find Oversold and Overbought Stocks Using Z-Scores in Python
How to Measure Earnings Quality: Cash Flow vs Net Income in Python
How to Build a Multi-Factor Stock Screen in Python (Value + Momentum + Quality)
How to Build a Simple DCF Model for Any Stock in Python
How to Screen Tech Stocks by Revenue Growth in Python
How to Screen Stocks by Balance Sheet Health in Python
Is "Sell in May" Real? SPY Monthly Seasonality Over 10 Years
How to Compare Sector Performance YTD Using Python
How to Screen Dividend Stocks by Yield and Quality in Python
How to Calculate Max Drawdown and Recovery Time for Any Stock in Python
How to Compare Profitability Across Mega-Cap Tech Stocks in Python
Why Ticker Symbols Are Unreliable: The Recycling Problem Every Quant Should Know
How to Calculate and Compare Stock Volatility in Python
How to Screen Blue-Chip Stocks by P/E Ratio in Python
How to Track Companies Through Ticker Changes, Bankruptcies, and Renames in Python
S&P 500 Turnover: How Much the Index Has Changed Since 2010
How to Calculate Stock Beta and Correlation in Python
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Altman Z-Score: Where To Get It in Python

Two routes, and the choice depends mostly on how many companies are involved. The Altman Z-Score is a weighted sum of five ratios, four of which come straight off a balance sheet and an income statement. The fifth needs the market value of equity, which no filing reports on a current basis. So either assemble the inputs yourself from SEC filings plus a price source, or read the finished number from an API that has already joined the two. In Python the second route is one call:

import xfinlink as xfl
xfl.set_api_key("YOUR_API_KEY")  # free at https://xfinlink.com/signup

xfl.metrics("KHC", period_type="ttm", fields=["altman_z_score"])

Edward Altman published the model in 1968 after fitting it on public manufacturers. Above 2.99 a company resembles the survivors in that sample, below 1.81 it resembles the firms that failed within two years, and the span between is the grey zone where the model declines to commit.

What goes into an Altman Z-Score?

Five terms, each carrying a weight fixed by the original discriminant analysis.

Term Weight What it measures Where the input comes from
Working capital / total assets 1.2 Short-term liquidity cushion Balance sheet
Retained earnings / total assets 1.4 Profit accumulated over the company’s life Balance sheet
EBIT / total assets 3.3 Operating earning power before financing and tax Income statement
Market value of equity / total liabilities 0.6 How far equity can fall before liabilities swallow the firm Share price and share count
Revenue / total assets 1.0 Asset turnover Income statement

Two features of that table drive most of what you will see. Operating earnings carry the heaviest coefficient, so a loss-making year moves the score further than any balance-sheet item does. And the fourth term is the only one that changes while the market is open, which makes a Z-score partly a market opinion rather than a pure accounting measurement. A company can drift from the safe zone into the grey zone without filing anything.

What score counts as distressed?

Below 1.81 is the distress zone, above 2.99 the safe zone, and the middle is deliberately undecided. Those cut-offs came from a small sample of manufacturers in the 1960s, which is worth remembering before treating 1.79 and 1.83 as different answers.

Read the score as a screen rather than a verdict. It ranks a large universe quickly and tells you which names deserve a reading of the actual filings; it does not tell you that a company will default, and it says nothing at all about whether the equity is cheap. The market-based distance-to-default measure answers a related question from the opposite direction, using volatility rather than accruals, and the two disagree often enough to be worth running together.

Can you build it from SEC filings alone?

Four of the five terms, yes. The SEC states that its EDGAR APIs “do not require any authentication or API keys to access”, and the companyfacts endpoint “returns all the company concepts data for a company into a single API call”, which covers working capital, retained earnings, revenue and the asset and liability totals.

The market value term is the one that breaks. A 10-K does carry a market figure on its cover page, the aggregate public float, but it counts only the shares held by non-affiliates and it is measured once a year at the end of the second fiscal quarter. Apple’s fiscal 2025 filing reports a public float of $3,253,431,000,000 as of 28 March 2025, against a market capitalisation of $4.58 trillion when the numbers below were pulled. Substituting the cover-page figure would put the fourth term roughly thirty per cent low and leave it stale for up to a year, so a price source is not optional.

There is also the assembly work. EBIT is usually not a tagged concept in a filing; it is derived. Retained earnings appear under different tags for filers that carry an accumulated deficit. For two or three companies this is an afternoon’s work and EDGAR alone is the right answer, since it is free, authoritative and updated within a minute of a filing. For a universe it becomes a mapping project that you then own forever.

How do you pull the score in Python?

One request per company, which keeps the example inside the free plan’s one-ticker-per-request limit.

import xfinlink as xfl
import pandas as pd

xfl.set_api_key("YOUR_API_KEY")  # free at https://xfinlink.com/signup

rows = [xfl.metrics(t, period_type="ttm", fields=["altman_z_score", "piotroski_f_score"])
        for t in ["AAPL", "NVDA", "LUV", "F", "KHC", "JPM"]]
table = pd.concat(rows)
print(table[["ticker", "period_end", "altman_z_score", "piotroski_f_score"]].to_string(index=False))
ticker period_end altman_z_score  piotroski_f_score
  AAPL 2026-06-27          12.55                  8
  NVDA 2026-04-26          55.35                  7
   LUV 2026-06-30           2.22                  7
     F 2026-03-31           0.89                  3
   KHC 2026-06-27           0.52                  4
   JPM 2026-06-30           None                  5

Nvidia at 55.35 shows the fourth term dominating: a five trillion dollar market value against a small liability base pushes the score somewhere no manufacturer in the original sample ever sat. Southwest at 2.22 sits in the grey zone for a structural reason rather than a worrying one, because airlines run negative working capital by design, having taken cash for flights not yet flown. Ford at 0.89 reflects a captive finance arm that puts a lending book on the balance sheet of a manufacturer. Kraft Heinz at 0.52 is the case the model was built to catch: an accumulated deficit after years of write-downs, and an operating loss over the trailing four quarters.

None of those four is a prediction of bankruptcy. Each is a reason to read further, which is what a screen is for.

Why is the score empty for a bank?

JPMorgan returns nothing, and that is the correct answer rather than a gap. Banks and most REITs present an unclassified balance sheet with no current-asset subtotal, so the first term has no inputs and the ratio has no meaning. Insurers sit in the same position.

Serving a number anyway would be worse than serving nothing. The score would compute, look plausible next to its peers, and rank an entire sector on a formula that was never fitted for it. Any provider that returns a Z-score for a large bank is telling you something about its own conventions.

How do you check a score you did not compute?

Pull the inputs and rebuild it. This is the test that separates a served metric from an opaque one, and it takes about ten lines.

f = xfl.fundamentals("KHC", period_type="quarterly", period="2y",
                     fields=["current_assets_total", "current_liabilities_total",
                             "retained_earnings", "ebit", "revenue",
                             "total_assets", "total_liabilities"]).sort_values("period_end")
q, ttm = f.iloc[-1], f.tail(4)
mc = xfl.metrics("KHC", period_type="ttm", fields=["market_cap"])["market_cap"].iloc[0]

z = (1.2 * (q.current_assets_total - q.current_liabilities_total) / q.total_assets
     + 1.4 * q.retained_earnings / q.total_assets
     + 3.3 * ttm.ebit.sum() / q.total_assets
     + 0.6 * mc / q.total_liabilities
     + 1.0 * ttm.revenue.sum() / q.total_assets)

print(f"balance sheet {str(q.period_end)[:10]}  working capital "
      f"{q.current_assets_total - q.current_liabilities_total:,.0f}M")
print(f"retained earnings {q.retained_earnings:,.0f}M  EBIT (4q) "
      f"{ttm.ebit.sum():,.0f}M  market cap {mc:,.0f}M")
print(f"recomputed Z {z:.2f}")
balance sheet 2026-06-27  working capital 535M
retained earnings -9,291M  EBIT (4q) -3,177M  market cap 30,030M
recomputed Z 0.52

The recomputed figure matches the served one, and the components can be checked one level further down: the retained earnings term of -9,291 million is the accumulated deficit Kraft Heinz reports in its own filing for the quarter ended 27 June 2026. A score that reproduces from published inputs is a score you can defend in a memo. Every field used above comes from the same endpoints, documented in the metrics reference, with history depth by plan set out on the pricing page.

Frequently asked questions

Does the Z-score change every day? Yes, through the market-value term. The four accounting terms update when the company files, so between filings the score moves only with the share price. A screen run on Monday and repeated on Friday will not return the same ranking.

Can the score be used to pick short candidates? Not on its own. A low score identifies a balance sheet that looks like historical failures, which is already widely known and often already in the price. It works better as a filter on a universe before a valuation screen than as a signal in its own right, and the same applies when building a screener around any single score.

Should the inputs be annual or trailing twelve months? Trailing twelve months for the flow items, so the score reflects the most recent four quarters rather than a fiscal year that may have ended eleven months ago. Balance-sheet terms take the latest reported values. The reasoning behind that split is covered in annual versus quarterly data.

Built with xfinlink — free financial data API for Python. pip install -U xfinlink

Built with xfinlink — free financial data API for Python. pip install -U xfinlink
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