The Associated Press reports the revelation came as the Democratic candidate for governor released tax returns dating to 2004.
GOP Gov. Rick Perry, who's seeking re-election, has criticized White for not providing details about his wealth and business relationships.
The returns White released yesterday show he made more than $1 million a year from 2004-2008, while mayor.
White helped line up private companies to provide goods and services during and after Rita. One of those was Btec Turbines, where White served on the board before he was mayor.
White later invested about $1 million in privately held Btec.
White says he made the investment for the same reason that he called Btec during the crisis -- the company was good at what it did.