The Japanese NTT Data Corp. is in exclusive negotiations to acquire Perot Systems, the information-technology consulting division of the American Dell Inc., although differences over price persist, according to sources familiar with the matter. The deal would be NTT Data’s most significant overseas acquisition as it seeks to expand in the U.S. and boost its offering in so-called knowledge process outsourcing, which has become popular with businesses looking to cut costs.

NTT Data has so far prevailed in an auction for Perot Systems, although it has yet to agree on a price with Dell, which has been seeking more than $5 billion in a potential divestment, the people said Friday, cautioning that no deal is certain.

NTT Data may seek to buy only parts of Perot Systems in the event it cannot agree on a deal with Dell for the entire division, one of the people said. The talks between the two companies are expected to continue for the rest of the month, another of the sources added. The sources asked not to be identified because the negotiations are confidential.

Representatives of NTT Data and Dell did not immediately respond to requests for comment.

Perot Systems is a major provider of IT consulting to hospitals and government departments. Founded in 1988 by former U.S. presidential candidate Ross Perot, it was acquired by Dell in 2009 for $3.9 billion.

Dell is hoping a sale of Perot Systems will help it trim its debt load following its cash-and-stock deal to acquire the data storage company EMC Corp. The agreement was worth $67 billion when it was agreed last October. It is scheduled to close between May and October, subject to approval by EMC shareholders.

Dell will have $49.5 billion in debt as a result of the deal. This week, banks syndicating the first $10 billion chunk of loans backing the deal with EMC pushed back the deadline for commitments by debt investors, citing the Lunar New Year holidays in China.

Business services companies Atos SE, Cognizant Technology Solutions Corp. and Tata Consultancy Services Ltd. had also previously participated in the auction for Perot Systems.

Dell has also been speaking to buyout firms about selling Quest Software, which helps with IT management, as well as SonicWall, an email encryption and data security provider. These negotiations have been challenged because of the rout in the leveraged-finance market. Together, Quest and SonicWall could be worth as much as $4 billion.

Based in Tokyo, NTT Data is one of the world’s largest technology services companies. It is present in more than 40 countries and generates more than $100 billion in annual revenue. It has a market capitalization of 1.55 trillion yen ($13.65 billion).