Pacific Investment Management Co., whose founder Bill Gross runs the world's biggest bond fund, has seen assets under management exceed over $1 trillion, underscoring investors' appetite for yield and portfolio diversification.

According to the Newport Beach, Calif.'s website on Thursday, Pimco's assets have hit $1.001 trillion as of the end of December 2009, up from $941 billion at the end of the third quarter of last year.

(Reporting by Jennifer Ablan; Editing by Diane Craft)