A shareholder of Sonic Corp. has sued in Delaware federal court to halt the drive-in fast food company’s $2.3 billion bid to take the company private, alleging that the board withheld key financial data about the deal.

The class action lawsuit, filed Nov. 2, seeks to enjoin a planned vote on Sonic’s proposed sale to Inspire Brands Inc. until the company provides more details about the process, potential conflicts and financial projections that investors said were omitted from regulatory filings earlier this year.