UPDATE 2-EU exec set to fine Intel on May 13 -sources

* Commission set to rule against Intel - sources

* Will order changes to how it provides rebates

* Intel shares down 3.9 pct

(Adds share price, byline)

By Foo Yun Chee and David Lawsky

BRUSSELS, May 7 (Reuters) - The European Commission is set to rule next week that the world's largest chipmaker, Intel Corp (INTC.O: Quote, Profile, Research), breached antitrust rules and will fine it and order changes to how it provides rebates, sources said on Thursday.

Sources familiar with the case told Reuters the Commission was expected to make its decision on May 13 during the EU executive's weekly meeting, based on a recommendation by Competition Commissioner Neelie Kroes.

"The Commission has an ongoing antitrust case against Intel. I cannot comment on the timing of the decision," spokesman Jonathan Todd said.

Intel shares were down 3.9 percent to $15.51 by 1742 GMT, underperforming a 1.4 percent lower Dow Jones industrial average .DJI.