Three small rivals have dropped their antitrust complaints against International Business Machines Corp that had triggered one of two investigations by EU regulators into IBM's business practices.

Emulator software vendor T3 Technologies Inc has withdrawn its complaint to the European Commission while Texas-based Neon Enterprise Software has agreed to relinquish its claim, the U.S. technology services company said in a regulatory filing.

French company TurboHercules said on Wednesday it was no longer pursuing its complaint filed with the EU watchdog due to business reasons. The allegations prompted a Commission investigation in July last year.

The Commission said it had no comment on the issue. The regulator could now decide either to continue or scrap the investigation. IBM declined to comment.

The Commission had on its own initiative opened a second investigation into allegations of discriminatory behavior by IBM toward competing suppliers of mainframe maintenance services in July last year.

IBM had said at the time of the allegations that Microsoft and other competitors had inspired the actions by T3 and TurboHercules.

T3 filed its complaint in January 2009 and TurboHercules in March 2010. Both companies had claimed that IBM tied the sales of its mainframe computers to its dominant mainframe operating systems. Neon had in July last year accused IBM of conduct that disparaged its product.

Many big companies and government institutions use mainframes, which are powerful computers, to store and process critical information.

(Editing by David Brunnstrom)

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