Interview Question Help: How does a decrease in tax rate affect WACC?

I understand it increases after-tax cost of debt, because the tax shield benefit is lessened.

However, I don't understand how/why it affects cost of equity.

Mechanically, when you unlever and relever the beta, aren't you using the same tax rate? Say you have a comp set of 5 companies all with a 20% tax rate. Your target company also has a 20% tax rate. If all tax rates go down to 10%, wouldn't you unlever the comp set at 10% tax rate and re lever at the 10% tax rate also? So aren't you getting the same beta even if tax rates stayed the same at 20%?

In a related example, say the tax rate only changes for your target company. You'd unlever the peer set at 20% and relever at the target company's expected tax rate of 10%?

3 Comments
 

Et voluptate sapiente vel quasi quod et in. Dolorum facere totam est id voluptates dolorem sequi odio. Quo odio hic sit maiores maxime accusantium quia.

Career Advancement Opportunities

July 2026 Investment Banking

  • Evercore 01 99.4%
  • Moelis & Company 01 98.9%
  • JPMorgan 01 98.3%
  • Guggenheim Partners 01 97.7%
  • Morgan Stanley 07 97.1%

Overall Employee Satisfaction

July 2026 Investment Banking

  • Moelis & Company No 99.4%
  • Evercore No 98.8%
  • Morgan Stanley 01 98.3%
  • BMO Capital Markets 12 97.7%
  • Banco Santander 01 97.1%

Professional Growth Opportunities

July 2026 Investment Banking

  • Evercore 01 99.4%
  • Moelis & Company 01 98.9%
  • Morgan Stanley 06 98.3%
  • Goldman Sachs 01 97.7%
  • JPMorgan 01 97.1%

Total Avg Compensation

July 2026 Investment Banking

  • Vice President (15) $434
  • Associates (46) $258
  • 3rd+ Year Analyst (8) $210
  • 2nd Year Analyst (22) $179
  • Intern/Summer Associate (13) $156
  • 1st Year Analyst (80) $150
  • Intern/Summer Analyst (73) $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

1
redever's picture
redever
99.2
2
kanon's picture
kanon
99.0
3
Secyh62's picture
Secyh62
99.0
4
BankonBanking's picture
BankonBanking
99.0
5
Betsy Massar's picture
Betsy Massar
98.9
6
GameTheory's picture
GameTheory
98.9
7
DrApeman's picture
DrApeman
98.9
8
dosk17's picture
dosk17
98.9
9
CompBanker's picture
CompBanker
98.9
10
bolo up's picture
bolo up
98.8
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...”