Investment income also must be taken into account. If you collect too much of this unearned income, it could disqualify you. For 2016 returns, if you made more than $3,400 in investment income, you cannot file for the earned income credit. For 2017, the limit is $3,450. Married couples who file separate returns are not eligible for the earned income credit. If you are married but your spouse did not live in your home for the last six months of the year, you may be able to file as head of household and take the credit.