finance professor james angel said many would-be investors thought they were buying the new, post-bankruptcy g.m., when, in fact, they were buying g.m.'s cast off parts-- the assets that are still languishing in bankruptcy court and might be stuck there for years. >> many of the online news wires basically said "general motors, gmgmq today emerged from bankruptcy. " so many people thought, ah ha! i can buy stock in the new company now, but it wasn't the new company they were buying. it was the corpse of the old company. >> reporter: when g.m. went bankrupt, its old stock got a new trading symbol-- gmgmq. that confused some investors so regulators have given the old company a new name-- motors liquidation company. the financial industry regulatory authority's john gannon wants everyone to know buying stock in motors liquidation or any bankrupt company usually means you are buying a lemon. >> people who think, if they buy >> reporter: regulators did not halt trading in the old g.m.'s shares until just after 2:00 p.m. last friday-- too late professor angel says. but gannon says securities law requi