Ohio gubernatorial Republican candidate Vivek Ramaswamy was hit with an ethics complaint over how he filed credit card payments in his campaign finance report, adding new drama to the neck-and-neck battle between the billionaire entrepreneur and Democrat Amy Acton.

State Senate Democrats filed the complaint with the Ohio Secretary of State on Tuesday, alleging Ramaswamy violated campaign finance laws by failing to disclose what roughly $500,000 in credit card payments were used for.