The stock market had a big rally on Thursday of this past week. It was due mainly to the successful initial public offering (IPO) from General Motors.

The auto company began trading again as a public company after filing for bankruptcy and being bailed out by Uncle Sam. The money realized from the IPO will add to the $9.5 billion already paid back to the US government by General Motors.

But GM will still owe the taxpayers plenty...Investors will recall that GM became 'Government Motors' after the multi-billion bailout from Uncle Sam.

The IPO's initial success is largely due to the fact that the IPO was priced to sell. After all, neither the company nor its majority owner – the US government – could afford to see the IPO flop. After the IPO, Uncle Sam's stake in the carmaker has fallen to about 40 per cent from its prior 61 per cent.

But is General Motors really much different from the company that went into bankruptcy?

General Motors restructured its operations and finances in last year's $60 billion government bailout. Thanks to the restructuring, GM in 2010 posted net profits and positive cash flow for the first three quarters of this year.

There are positive factors going for GM, such as its $33 billion in cash at the end of the second quarter. In addition, it will enjoy $45 billion in tax-loss carry-forwards which will shield its earnings from the IRS for awhile.

GM is still a major player in the auto industry. GM will hold on to its spot this year as the world's second-largest automaker after Toyota Motor.

And perhaps most importantly, General Motors is playing up its growing international business. GM sells more than two-thirds of its vehicles outside of North America.

In particular, the company emphasizes that it plans to continuing strengthening its international presence in emerging markets. GM has the top combined market share (13%)across the BRIC emerging markets of Brazil, Russia, India and China.

But GM is struggling in Europe. And its market share in the United States has slipped by nearly a point over the past year to 19 per cent in January through September.

However, the real “sword of Damocles” hanging over General Motors is the company's long-term pension obligations.....

The optimists on GM are quick to point out that the bankruptcy eliminated much of the company's debt. True enough, but they are ignoring the company's massive pension obligations.

General Motors' pension fund is the largest private sector pension plan in the world with approximately $100 billion in liabilities.

The essential flaw in the entire GM rescue was that, in order to keep the United Auto Workers union happy, the pension plan was transferred completely untouched to the 'new' General Motors.

GM is making no contributions to the pension fund now. But the company says it may have to put in $4.3 billion in 2014 and $5.7 billion in 2015. GM has said that it will “possibly” have to add even more funds in the future. Investors should change the word possibly to definitely.

That huge pension liability is a red flag. It may land General Motors right back in bankruptcy court some day down the road.

The future outlook for the 'new' General Motors may not be as rosy as the company, the government and Wall Street suggests. It looks likely that the 'new' GM may end up looking a lot like the 'old' GM.