SAN FRANCISCO - Blockbuster Inc. shares plunged further into penny-stock territory Wednesday after the struggling home-video-rental company said in a regulatory filing that it will likely file for bankruptcy if it's unable to address its debt load. Shares of Blockbuster fell 12 cents, or 29 percent, to 28 cents a share. The company's market capitalization now totals about $34 million, or just a fraction of its fourth-quarter revenue of $1 billion.

- MarketWatch