Impact of tax rate on cost of equity

I understand why changes in the corporate tax rate impact WACC from a cost of debt perspective since we multiply CoD by (1 - tax rate) to reflect the impact of the interest tax shield.

However, I'm struggling to understand why a change in the tax rate would affect cost of equity (as BIWS guides claim). If we're looking at CAPM, the only place the tax rate could conceivably have some impact is the beta calculation. The guides claim that since our calculation to relever industry average unlevered beta will now use the higher tax rate, the final levered figure will come out lower. However, wouldn't we be applying the same tax rate when we initially unlever those betas?

Or, is the idea that we use the old tax rate to unlever historical betas since they reflect historical market activity, but we apply the new tax rate to relever the average industry beta since that's where we expect our company's beta to reach over time?

2 Comments
 

I think tax rate is included in levered ß which should be unlevered ß * (1 +D/E *(1-tax)) if i recall correctly, so this would be reflected in the cost of equity 

 

Aliquid dolores sed aut et quaerat tenetur rerum. Quo id sed id quo voluptatem ducimus sequi. Officiis delectus consequatur ad adipisci.

Aliquam voluptas neque iste quis temporibus. Sequi architecto eligendi quos voluptatem dolores. Soluta est ut accusamus veritatis ea nostrum. Atque eius voluptate cumque vero. Enim expedita est quas aut ut at.

Career Advancement Opportunities

September 2026 Investment Banking

  • Evercore 01 99.5%
  • Moelis & Company 01 98.9%
  • JPMorgan 01 98.4%
  • Goldman Sachs 01 97.8%
  • Morgan Stanley 07 97.3%

Overall Employee Satisfaction

September 2026 Investment Banking

  • Moelis & Company No 99.5%
  • Morgan Stanley 02 98.9%
  • Evercore 01 98.4%
  • Banco Santander 02 97.8%
  • BMO Capital Markets 12 97.3%

Professional Growth Opportunities

September 2026 Investment Banking

  • Evercore 01 99.5%
  • Moelis & Company 01 98.9%
  • Morgan Stanley 07 98.4%
  • Goldman Sachs 01 97.8%
  • JPMorgan No 97.3%

Total Avg Compensation

September 2026 Investment Banking

  • Vice President (16) $429
  • Associates (51) $260
  • 3rd+ Year Analyst (8) $210
  • 2nd Year Analyst (26) $182
  • Intern/Summer Associate (14) $159
  • 1st Year Analyst (84) $151
  • Intern/Summer Analyst (76) $101
notes
16 IB Interviews Notes

“... there’s no excuse to not take advantage of the resources out there available to you. Best value for your $ are the...”

Leaderboard

success
From 10 rejections to 1 dream investment banking internship

“... I believe it was the single biggest reason why I ended up with an offer...”