Repay Mortgage or Invest in Roth IRA?
April 17, 2006, Revised July 17, 2006
"I have $500 a month available for investment. Should I put it in a Roth
IRA, or use it to repay principal on my 6.50% mortgage? I am 35 years
old and in the 33% tax bracket."
I would put the maximum contribution (currently $4,000 a year for
someone your age) in the Roth IRA, invested in a diversified portfolio
of common stock, and use the remainder to pay down my mortgage balance.
Repaying a mortgage is an investment with a yield equal to the mortgage
interest rate. Since you can deduct 1/3 of the interest from your taxes,
you save only 2/3 of the interest when you repay the loan. Your
after-tax yield is thus 6.5(1 - .33) = 4.33%.
Roth IRAs pay no taxes, but even so funds invested in low-risk assets
won’t do much better than 4.33% today. At age 35, however, you should
not have a conservative IRA portfolio. I would put the IRA in an indexed
common stock fund, which should yield 9% or more over the next 30 years,
with no taxes due on it ever. Since your contribution limit is $3,000,
use the balance to pay down your mortgage.