IBM ( IBM) is in talks to buy Sun Microsystems ( JAVA), the Wall Street Journal reports, citing people familiar with the matter. A combination of the two companies would bolster IBM's heft on the Internet, in software and in finance and telecommunications markets, the Journal notes. Talks are under way, but people familiar with the matter said a transaction might not occur and the talks could end without a deal being reached. An IBM spokesman declined to comment for the Journal, while a spokesman for Sun didn't return calls requesting comment. If a deal does go through, which could happen as early as this week, IBM is likely to pay at least $6.5 billion in cash to acquire Sun. That would be a premium of more than 100% over Sun's closing price Tuesday of $4.97, the newspaper reports. Both companies make computer systems for corporate customers that aren't reliant on Microsoft's ( MSFT) Windows software, and their product lines are less dependent than rivals' on Intel's ( INTC) microprocessor technologies, the Journal notes. The two companies are also strong supporters of open-source Linux and Java software. Sun has approached a number of large tech companies recently in the hopes of being acquired, the Journal reports. Hewlett-Packard ( HPQ) declined the offer, said a person briefed on the matter. A spokesman for Dell ( DELL) declined to comment. The Journal says any transaction would strengthen IBM's position against rival H-P. It could be the largest acquisition in IBM's history, surpassing the acquisition of Cognos last year, according to the newspaper.