Modigliani and Miller
Proposition 2 (with tax)
Takes the cost of equity a company would have with no debt at all, and adds a premium for the financial risk that borrowing creates. It does in one step what ungearing and regearing a beta does in two.
ke cost of equity in the geared company · kei cost of equity if it were ungeared · kd cost of debt · T corporation tax rate
From the September 2024 sitting the sheet also prints a rearranged version, which solves for the ungeared cost of equity instead. Before that, you had to do the algebra yourself under exam pressure — and a lot of candidates did not.
This is a real second formula, unlike the asset beta formula, where the two terms are just the equity and debt halves of one weighted average. Toggle the calculator below to see the sheet’s two versions working in opposite directions.
Equity must be above zero.
See the worked example
An ungeared company in the same industry has a cost of equity of 12%. Your company is financed 60% equity and 40% debt by market value, borrows at 6%, and pays tax at 30%.
- Gearing: Vd ÷ Ve = 40 ÷ 60 = 0.6667
- The spread between ungeared equity and debt: 12 − 6 = 6%
- Scale it for tax relief and gearing: 0.7 × 6 × 0.6667 = 2.8%
- Add it back: 12 + 2.8 = 14.8%
Flip the calculator to the other direction with 14.8% in the box and you get 12% back. That is the rearranged version doing its job.
Vd ÷ Ve is debt over equity, not debt over total finance. A company described as 40% geared could mean either, so read the definition the question gives rather than assuming.
This and the asset beta route should give roughly the same answer on the same facts. Where a question gives you a proxy company’s beta, use beta. Where it gives you an ungeared cost of equity directly, use M&M. Choosing the longer route still earns the marks, but it costs time you do not have in AFM.