Buyout shops have been known to hold onto their investor’s money for as much as seven to 10 years, but one New York firm is taking lockups to new lengths.

American Securities, a middle-market buyout firm, has closed its latest offering, American Securities Partners V, with committed capital of more than $2.3 billion. The lockup? Twenty-five years.

“Our investors understand our enthusiasm to help managers build their companies for the long-term,” said American Securities CEO Michael Fisch. “The unique 25-year investment horizon of this partnership will allow us to continue to create high long-term, risk-adjusted rates of return for our management partners and investors.”

American Securities was founded in 1947 as the family office of William Rosenwald, heir to the Sears Roebuck fortune.