HBK Investments, the largest shareholder of Circuit City Stores, is pushing the electronics retailer to accept an unsolicited bid from Blockbuster Inc. The Dallas-based hedge fund also indicated it might help finance the deal.

“We are very optimistic about the future prospects of a combined company,” HBK wrote to Circuit City CEO Philip Schoonover. It called on the Richmond, Va.-based electronics retailer, in which it owns a 9.1% stake, to “immediately” provide information to Blockbuster, and threatened to file a lawsuit if the board refuses to do so.

“We see little downside to Circuit City’s business by allowing Blockbuster to conduct full due diligence,” HBK, which also owns an 8.5% stake in the video rental chain, said. So positive is the firm that it “might also be prepared to provide financing” for the acquisition.