The Wall Street Journal reports that Hewlett Packard (NASDAQ: HPQ) will spend $12.8 billion to buy Electronic Data Systems (NYSE: EDS). While this combination would make HP the second largest, behind International Business Machines (NYSE: IBM) in computer services, this may not be a good way to spend $12.8 billion.

That's because EDS and HP would under perform in services when it comes to profitability. EDS's bigger business earned a 1% net profit margin in the first quarter. But HP's services business generated a far higher 9% estimated net margin. Unfortunately -- for reasons described below -- the combined company will probably have lower margins.

Meanwhile, IBM's profit lagged HP's slightly -- it made an estimated 7% net margin in the first quarter in its services business. But IBM is and will remain a much bigger player. Combined, EDS and HP's services business will control 5.3% -- lagging IBM. That's because IBM controlled 7.2% of the tech-services market in 2007 while EDS was a distant second at 3% and HP was fifth, with a 2.3% share.

I think HP's most profitable business, printers, might be able to make better use of the $12.8 billion in capital. This Imaging and Printing Group earned a 13% estimated net margin. It grew a mere 4% to $7.3 billion in revenue and given that this unit is by far the most profitable in HP's stable of businesses, this would appear to be the best place to invest for future growth.

Now may be a good time to sell HP stock. Mark Hurd came into HP as a nuts-and-bolts operator. This deal suggests that Hurd has run out of growth options and that HP can't grow earnings through more cost cuts. I have no doubt that Hurd could cut costs once EDS has been integrated.

However, government work -- which accounts for the biggest part of EDS's revenue -- is inherently less profitable than the commercial work which HP performs in its services business. So, I would guess that the EDS merger will lower HP's services margins.

What HP really needs -- and lacks due to Hurd's particular skills -- is the ability to innovate as it did successfully in printers back in the 1980s and 1990s when it invented the highly profitable printer and ink business.

Peter Cohan is President of Peter S. Cohan & Associates. He also teaches management at Babson College and edits The Cohan Letter. He has no financial interest in the securities mentioned.