WASHINGTON – Industry regulators have fined Bank of America Corp.’s Merrill Lynch unit $500,000 because of oversight failures involving sales of college-savings products called 529 plans.

The Financial Industry Regulatory Authority also censured Merrill Lynch in a disciplinary action disclosed Tuesday.

FINRA found that Merrill Lynch failed to maintain adequate supervisory procedures to ensure that its representatives were considering the potential tax benefits of recommending a client choose a 529 plan in the state where he lives, rather than an out-of-state plan.

The plans allow money to be withdrawn for college expenses free of federal taxes.

In the time covered by the FINRA agreement, Maine’s NextGen was the only 529 that Merrill Lynch sold nationwide.