In Douglas Adams's final installment of the Hitchhiker's Guide trilogy, readers learn that Earth's dolphin community sent Mankind a parting note before departing our planet for others in far less danger of imminent vaporization: "So long, and thanks for all the fish." I'm checking my mailbox daily, waiting to receive a similar note from General Motors (NYSE: GM).

Yesterday, the U.S. government admitted that it's ready to throw in the towel on the GM IPO. The Treasury Department is preparing to sell its remaining 500 million-share stake in GM when its lock-up period expires.

Tailpipe dreams … of profit
Originally, the Feds had actually hoped to make a profit from bailing out the bankrupt automaker (as they've reportedly earned profits from similar subsidies offered to the likes of Bank of America (NYSE: BAC), Citigroup (NYSE: C), and Goldman Sachs (NYSE: GS).) But with GM's stock down more than 10% from its IPO price, things aren't working out quite as planned. Even with federal tax credits to help it, GM's still posting profit margins below those of rivals Ford (NYSE: F) and Honda (NYSE: HMC) -- although it's stolen a march on  the reeling Toyota (NYSE: TM), thank goodness.

Still, with a P/E ratio of 10, and most analysts projecting long-term growth of barely 10%, the stock looks only fairly priced today, and unlikely to gain much more without some new catalyst to boost it. With the 2012 election year just around the corner, the Obama administration is beginning to lose patience, and may be willing to take a loss in the interests of showing GM the door.

Reports suggest that Treasury could begin liquidating it remaining shares as early as May or June of this year. Breaking even would require that GM shares to fetch $53 apiece at the time, however. If the stock price doesn't recover by then, taxpayers could be looking at as much as an $11 billion loss on their $50 billion "investment" in GM. Worse, The Wall Street Journal warns that a flood of "warrants and stock" due to owners of "old-GM" bondholders could dilute the shares' value between now and then -- hurting the stock price and magnifying investors' losses.

Still, as GM shares fall back towards the price at which they were originally expected to IPO, the chances of new investors profiting will increase significantly. Want to cash in when that happens? Click here, and I'll tell you how.

General Motors is a Motley Fool Inside Value pick, Ford Motor is a Motley Fool Stock Advisor recommendation, and The Fool owns shares of both Bank of America and Ford Motor -- but Fool contributor Rich Smithdoes not own shares of any company named above. Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.