Dell has made an offer of $3.9bn to purchase Perot Systems in a bid to expand its range of IT services.

The deal could also potentially allow Dell to sell more hardware to existing Perot customers, the company said.

Dell's rival Hewlett-Packard expanded its own global services unit with the acquisition of EDS for $13.9bn in May 2008.

Over the last four quarters, Dell and Perot together had revenue of $16bn from enterprise hardware and IT services, with $8bn coming from enhanced services and support, Dell said. Perot's contribution to that is relatively small: In 2008, the company reported total revenue of $2.78bn.

At $30 (£18.50) per Perot Systems share, Dell's offer represented a significant premium over Friday's closing price of $17.91(£11.07).

The boards of Dell and Perot agreed the terms of the transaction on Sunday, they said. Dell expects to complete the deal in its November-to-January fiscal quarter.

Upon completion of the acquisition, Dell plans to make Perot Systems its services unit, and will put current Perot CEO Peter Altabef in charge of it. It also expects Ross Perot Jr, chairman of the Perot Systems board, to be invited to join the Dell board of directors.

The services unit will fit alongside Dell's existing divisions for selling to large enterprises, to government customers and to small and medium-size businesses. Dell created the three divisions in a major reorganisation of its business sales teams last December, shifting from a geographic structure to one aligned with customer types.

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