Form 497VPU MASSACHUSETTS MUTUAL

Supplement dated October 6, 2025

to the Prospectus and Updating Summary Prospectus,
each dated April 28, 2025 (each a “Prospectus”), as supplemented, for:

MassMutual Electrum^SM
Issued by Massachusetts Mutual Life Insurance Company

and to the Prospectus, Initial Summary Prospectus, and Updating Summary Prospectus,
each dated April 28, 2025 (each a “Prospectus”), as supplemented, for:

C.M. Life Electrum Select^SM

Issued by C.M. Life Insurance Company

 

THIS SUPPLEMENT MUST BE READ IN CONJUNCTION WITH YOUR PROSPECTUS. PLEASE RETAIN THIS SUPPLEMENT FOR FUTURE REFERENCE.

 

Effective September 25, 2025, this supplement amends certain information in the above-referenced prospectuses (“Prospectuses”). The information in Appendix A of the Prospectuses for the MFS^® Blended Research^® Core Equity Portfolio is deleted and replaced with the following:

 

Fund Type	Fund and Adviser/Sub-Adviser	Current Expenses (expenses/ average assets)	Average Annual Total Returns (as of 12/31/2024)
			1 Year	5 Year	10 Year
Large Cap Blend	MFS® Blended Research® Core Equity (Initial Class) Adviser: Massachusetts Financial Services Company Sub-Adviser: N/A	0.29%(*)	25.50%	15.15%	12.32%

 

^(*) This fund is subject to an expense reimbursement or fee waiver arrangement. As a result, this fund’s annual expenses reflect temporary expense reductions. See the fund prospectus for additional information.

 

If you have questions about this supplement, or other product questions, you may contact your registered representative, visit us online at www.MassMutual.com/contact-us, or call our Service Center at (800) 665-2654, 8 a.m.–5 p.m. Eastern Time.

 

For more information about the fund, read the fund prospectus. Prospectuses are available on our website at www.MassMutual.com.

 

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