Putnam Investments LLC will request U.S. Supreme Court review of a decision reviving a class action targeting the financial company’s 401(k) plan.

Putnam asked the U.S. Court of Appeals for the First Circuit Oct. 24 to delay enforcing its Oct. 15 decision against the company to allow time for filing a petition with the Supreme Court.

The case raises an important issue under the Employee Retirement Income Security Act that is ripe for Supreme Court review, Putnam said. Specifically, the case asks which litigants—the fiduciaries of ERISA-governed benefit plans or the people covered by those plans—have the burden of proving...