MetLife Inc. agreed to pay $25 million to settle a probe of abuses tied to variable annuities, the highest ever penalty for those products by the Financial Industry Regulatory Authority.

The sum includes a $20 million fine and $5 million to be paid to customers for “negligent” misrepresentation and omissions, FINRA said in a May 3 statement. The largest U.S. life insurer neither admitted nor denied wrongdoing.

Complex Products.

“Variable annuities are complex and expensive products that are routinely pitched to vulnerable investors as a key component of their retirement planning,” Brad Bennett, FINRA’s chief of enforcement, said in the...