The European Commission closed antitrust proceedings against Qualcomm as big technology companies dropped their four-year old complaints against the U.S. mobile chip supplier.

The Commission's decision came as Ericsson , the world's biggest mobile network equipment maker, and Texas Instruments , Qualcomm's biggest wireless chip rival, both announced that they were withdrawing their complaints.

The case, which kicked off in October 2005 with complaints from six large companies about Qualcomm's licensing practices, marks the end of some of Qualcomm's biggest legal disputes, except from an ongoing battle with Japanese regulators.

The closing of the case means Qualcomm could be in a better position to return more cash to shareholders through share buybacks or a dividend increase, UBS analyst Maynard Um said.

We believe there was some overhanging concern that the EU could fine Qualcomm, he said.

Ericsson said on Tuesday it withdrew its complaint because two Asian authorities had already ruled against the U.S. company. Texas Instruments, which is pulling out from the wireless chip market, also withdrew its complaint, saying it was encouraged by decisions made in Korea and Japan.

These withdrawals follow moves by Nokia and Broadcom Corp to drop their cases against Qualcomm as part of their settlements of bigger legal cases with the company. Other companies that filed complaints include NEC Corp <6701.T> and Panasonic <6752.T>.

All complainants have now withdrawn or indicated their intention to withdraw their complaints,, the EU executive said in a statement.

In view of this, the Commission does not consider it appropriate to invest further resources in this case.

San Diego-based Qualcomm is still appealing a ruling against it in Japan.

Qualcomm shares were down 1 cent at $45.54 on Nasdaq after the news.

(Reporting by David Brunnstrom and Yun Chee Foo in Brussels and Sinead Carew in New York; Editing by Derek Caney)

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