IndyCar announced Thursday it has agreed to refund $925,000 to fans who bought advance tickets to the Boston Grand Prix before it was canceled.

The motorsports series and Massachusetts Attorney General Maura Healey said the money represents less than half the nearly $2.1 million spent by about 4,000 fans. Healey said she has filed a lawsuit against Boston Grand Prix and chief executive officer John Casey, seeking full refunds for all ticket buyers.

Boston Grand Prix LLC had refunded customers approximately $400,000 before filing for bankruptcy protection earlier this week.

Tickets for the planned Labor Day Race went on sale in March, but the race was canceled in April. Organizers said the city made unreasonable demands, while city officials said the race course group was disorganized.

Mark Miles, CEO of IndyCar parent Hulman & Co., said he appreciated Healey's pursuit of the remaining money.