The wife of “bond king” Bill Gross filed for divorce last month. Sue Gross cited “irreconcilable differences” in a petition filed with the Los Angeles state court on Nov. 22.

The Grosses have been married for 31 years and have been generous philanthropists in Orange County.

The William and Sue Gross Family Foundation has given a total of almost $800 million, including a $40 million gift in January to create a nursing school at the University of California-Irvine.

The Business Journal estimates Bill Gross’ wealth at $2.6 billion.

He co-founded Newport Beach-based Pacific Investment Management Co. in 1971 and helped it grow to $2 trillion in assets under management at its peak.

He left PIMCO in 2014 to join Janus Capital Group Inc., where he manages the $1.7 billion Janus Global Unconstrained Bond Fund.