CREDIT SUISSE OPPORTUNITY FUNDS (the “Trust”)

Credit Suisse Floating Rate High Income Fund

Credit Suisse Strategic Income Fund

(each, a “Fund”)

Supplement to each Fund’s Summary Prospectus, Prospectus and Statement of Additional
Information (“SAI”), each dated February 27, 2026, as supplemented to date

Effective September 4, 2026, the Trust and each Fund will change its name as reflected in the table below. As such, effective September 4, 2026, all references to the Trust and each Fund’s current name in each Fund’s Summary Prospectus, Prospectus, and SAI are hereby deleted and replaced with the new name reflected in the table below.

Shareholders should retain this supplement for future reference.

Dated: July 15, 2026