Summary Prospectus by Investment Company (Form 497K)

MASSMUTUAL FUNDS

MML Barings Unconstrained Income Fund

Supplement dated February 27, 2026 to the

Prospectus dated February 1, 2026, and the

Summary Prospectus dated February 1, 2026

This supplement provides new and additional information beyond that contained in the Prospectus and Summary Prospectus. It should be retained and read in conjunction with the Prospectus and Summary Prospectus.

Effective immediately, the information for Omotunde Lawal found under the heading Portfolio Manager(s) in the section titled Management (on page 40 of the Prospectus) as well as under the heading Subadviser and Portfolio Managers in the section titled Management of the Funds on page 62 of the Prospectus, is hereby removed.

PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE

ADVPRO-26-01

UI-26-01