More and more retirees could soon be facing the choice of accepting a pension buyout or collecting a monthly check, says Marilyn Capelli Dimitroff, a financial adviser in Bloomfield Hills, Mich.

Few companies still offer traditional, defined-benefit pension plans, but millions of retirees are still collecting pensions. Earlier this year, General Motors Co. gave 42,000 of its 118,000 salaried retirees the option of taking a one-time payment in lieu of a traditional pension, in a bid to reduce the company’s overall pension liabilities. That followed a similar offer by Ford Motor Co. to many of its former employees.

“This could well be the beginning of a trend for many companies,” says Ms. Dimitroff, president of Capelli Financial Services Inc.