The Massachusetts Securities Division has fined the Boston-based brokerage LPL Financial Holdings Inc. $1 million for allegedly failing to supervise advisers operating out of the largest credit union in New England.

The state regulators alleged that LPL agents at Marlborough-based Digital Federal Credit Union were working for both the brokerage and the credit union. They were being paid bonuses by the credit union and used the name “DCU Financial’’ for their operation.

Secretary of State William F. Galvin, who oversees the Securities Division, said the employees did not make it clear to customers that they were being paid by both the credit union and LPL.

“Credit Union members are hard-working average investors who should not find themselves subject to these types of aggressive sales practices and misleading and confusing disclosures,’’ Galvin said in a statement.

LPL, which has had a series of run-ins with state and federal regulators in recent years, agreed to pay the fine and to remove the name DCU from its business name on the credit union premises. Also, LPL was ordered to review its policies, procedures, and training in connection with the credit union.

Jeffrey Mochal, a spokesman for LPL, said in a statement that the company “has made a long-term commitment to enhancing our risk management and compliance structures. We are pleased to have resolved this matter with the Massachusetts Securities Division.’’

Galvin’s office does not have jurisdiction over credit unions and did not name Digitial Federal Credit Union in its allegations. In a statement, the credit union said it cooperated with the division’s inquiry and is “committed to working with LPL’’ to address the issues.

“We have made every effort to comply with applicable rules and regulations, and we believe we have succeeded in placing our members’ interests first,’’ John LaHair, a spokesman for the credit union, said in a statement.

LPL has paid millions of dollars in fines since 2013 to state and federal regulators to resolve allegations ranging from the unsuitable sale of variable annuities and complex exchange-traded funds to failing to send out or create proper records.

LPL says it has made investments to improve its performance.

Last year, the company sought but failed to find a buyer. Its chief executive of 14 years, Mark Casady, retired in January and was succeeded by Dan Arnold.

Beth Healy can be reached at beth.healy@globe.com. Follow her on Twitter @HealyBeth.