For Dell Inc. (DELL), trying to become a one-stop technology shop comes at a hefty price.

The world's second-largest computer maker paid a steep premium to acquire Perot Systems Corp. (PER), especially when compared to Hewlett-Packard Co.'s (HPQ) similar acquisition of Electronic Data Systems last year. But Dell needed a big move into information-technology services to keep pace with H-P and other rivals as computer profits dwindle. Perot Systems' position in two still-strong markets - health care and government - makes the company a particularly felicitous purchase.

Round Rock, Texas-based Dell will pay $3.9 billion, or $30 a share, to buy the company H. Ross Perot founded in 1988. That represents a 76% premium to Perot Systems' average share price over the past month before the deal was announced, according to Dealogic, and sent Perot shares up more than 65% to $29.58 Monday.

In buying Perot Systems, Dell follows rival H-P's plunge into the services business with EDS (which, coincidentally, was founded in 1962 by Ross Perot). That $12.8 billion acquisition, completed in August 2008, represented a premium of 47% over EDS's one-month average share price.

Based on the comparison, Dell's acquisition looks costly by a number of valuation methods. BMO analyst Keith Bachman is "mildly enthusiastic" about the deal but said the acquisition is expensive based on a price-to-earnings ratio. Dell, he noted, is paying roughly 29 times Wall Street's average earnings estimates for 2010, while H-P paid 15 times EDS's 2009 earnings estimates.

On a price-to-sales basis, Dell's deal is 1.4 times Perot's sales, while H-P paid 0.6 times EDS's sales last year.

But compared to H-P, it's more crucial for Dell to diversify its revenue base into areas outside of its core businesses of selling computers and servers to corporate customers.

Before its EDS purchase, H-P had a wide customer base selling computers and services to consumers and businesses. Dell, however, generated only 10% of its revenue through services in its most recently reported quarter.

During a conference call with reporters, Chairman and Chief Executive Michael Dell said his company plans to grow its now-larger services business with smaller acquisitions and organic growth.

And Perot Systems' focus on health care and government in the U.S. could offer strong prospects as health-care reform bills wend their way through Congress and government spending increases as a result of federal stimulus packages.

Shares of Perot Systems haven't suffered the steep declines of the broader markets over the past two years. Before Monday's announcement, the stock was up 12% from September 2007, significantly better than the more than 20% declines of broader market indexes during the same period.

The Morgan Stanley Technology Index is down more than 15%, while Dell has fallen 37% over that time frame.

In a note to clients, JPMorgan analyst Mark Moskowitz called the acquisition a "good stepping stone" for Dell to move beyond its reliance on personal computers.

"We do see the building block as being compelling, but the purchase price seems relatively rich," he said.

In recent trading, Dell was off 73 cents, or 4.4%, at $15.96; Perot Systems was ahead $11.64, or 65% at $29.55. Hewlett-Packard was up 20 cents, or 0.4% at $46.35.

-By Jerry A. DiColo, Dow Jones Newswires; 212-416-2155; jerry.dicolo@dowjones.com