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Case study · Capital allocation

GM won the decade. Its returns fell every single year.

A ten-year return-on-capital study of GM, Ford and Stellantis (FY2016–FY2025), built end to end from 62 SEC filings, with the captive finance arms taken out to measure the car business itself.

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13.9%

GM: 10-year ROIC, capital-weighted

11.0%

Stellantis (FCA before 2021)

-2.6%

Ford

62

SEC filings parsed, ~160K XBRL data points

Findings

The best allocator, in steady decline

GM was Detroit’s best capital allocator of the past decade, with a 13.9% capital-weighted return on invested capital, ahead of Stellantis at 11.0% and Ford at −2.6%.

But GM’s return also fell every single year, from 37% in FY2016 to 0.6% in FY2025. FY2025 was hard on all three once write-downs are included: Ford fell to −63% and Stellantis to −27%.

The hard part was comparability. GM Financial and Ford Credit carry 84–91% of their parents’ debt, so leaving them in would bury the car business under a lender’s balance sheet. I took them out to measure automotive returns on their own.

ROIC
NOPAT (25% tax) ÷ average (debt + equity − cash)
Scope
GM and Ford: automotive only (GM Financial and Ford Credit removed). Stellantis = FCA N.V. before 2021
Accounting
GAAP / IFRS as reported, including FY2025 write-downs
Sources
10-K and 20-F filings via SEC EDGAR XBRL; EUR→USD at the FRED DEXUSEU annual average
Completed
September 2026
Tools
Python, Excel

Chart

Return on capital, FY2016–FY2025

Line chart of annual return on capital for GM, Stellantis and Ford, FY2016 to FY2025. GM falls every year from 37% to 0.6%; Ford ends at −63% and Stellantis at −27% in FY2025.
Annual ROIC by company. GM and Ford: automotive business only. Stellantis = FCA N.V. before 2021. Source: GM, Ford, FCA/Stellantis 10-K and 20-F filings (SEC EDGAR XBRL).

Method

Built end to end, then checked

  1. 01

    Parse the filings

    A Python pipeline pulls ~160K XBRL data points from 62 10-K and 20-F filings on SEC EDGAR.

  2. 02

    Separate the lenders

    GM Financial and Ford Credit, 84–91% of parent debt, are removed so ROIC measures the automotive business.

  3. 03

    One definition for all three

    NOPAT at a 25% tax rate over average debt plus equity minus cash; Stellantis converted to US dollars at the FRED annual average.

  4. 04

    Rebuild it in Excel

    A 1,898-formula Excel model with sensitivity analysis, matched to the Python output with zero mismatches.

  5. 05

    Check against the source

    21 of 21 spot checks against the original filings passed.

1898

formulas in the Excel model

0

mismatches against the Python output

21/21

spot checks passed against the filings

10

fiscal years, FY2016–FY2025

Want to go through the model?

Email me and I’ll walk you through the data pipeline, the adjustments and the checks.

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