Warren Buffett has recently suggested that tax rates don’t matter when making investment decisions. Clifford Asness of AQR Capital Management respectfully disagrees (via the WSJ):
Consider how every business-school student, investment banker and investment analyst on Earth has been taught to choose whether to invest in a specific project or company. You make a spreadsheet (a napkin will do sometimes). You put in your best guess of the future cash flows, and you discount those cash flows back to the present at some required rate of return you believe reflects the risk entailed. Of course, opinions about the future cash flows and the proper discount rate can vary widely, but the essential methodology is ubiquitous.
Now here’s the kicker: Nobody who pays taxes and has ever done this exercise has failed (while sober) to use after-tax cash flows in this calculation. Somewhere in the spreadsheet there is a number, say 20%, or 28%, or a Gallic 75%, representing the taxes you’ll pay on the assumed cash flow—and you only count the amount you’ll get after paying this tax. If you turn the tax rate up high enough, projects or companies that looked like good investments become much less attractive and vice versa. Mr. Buffett is undoubtedly right that rich people will continue to invest some amount in something regardless of the tax rate (except for a 100% rate!). He’s also undoubtedly right that an investment that easily clears all hurdles will likely still be attractive after a small tax increase. But life, and the investment decision, occurs at the margin. Fewer and smaller investments will be made if the after-tax prospects are worse. It’s just math and logic, unassailable and commonly accepted regardless of one’s political persuasion.