Berkshire Hathaway, billionaire Warren Buffett's investment company, sold its stake in Ameriprise Financial earlier this year, according to a regulatory filing on Thursday.

Berkshire previously owned 661,742 Ameriprise shares, according to a filing with the U.S. Securities and Exchange Commission.

The company disclosed some of its holdings as of the end of March on Thursday, and Ameriprise was not on the list.

Berkshire also increased stakes in the following companies at the end of the first quarter: Kraft Foods Inc, Burlington Northern, Santa Fe Corp, Ingersoll-Rand Co Ltd , U.S. Bancorp, Wells Fargo & Co and WellPoint Inc. Meanwhile, the company lowered its holding in Iron Mountain Inc.