By Ian Sherr

San Francisco (Reuters) - Former Advanced Micro Devices Inc <AMD.N> Chief Executive Hector Ruiz will step down as chairman of contract chip maker Globalfoundries, following reports linking him to the largest hedge-fund insider trading scheme ever.

Ruiz will immediately take a voluntary leave of absence and will be resigning from the company January 4, Globalfoundries said in a statement on Monday.

The company said Ruiz submitted his resignation in September, but would not comment on the reason for his decision.

"He's reaching retirement age," said FTN Equity Capital Markets analyst Joanne Feeney, who added that, while Ruiz played a role in the deal spinning off chipmaker GlobalFoundries from chip-designer AMD, he has been mostly hands-off since then.

"In my opinion, it doesn't affect the company in any way," said Feeney, who has a buy rating on the stock.

Alan "Lanny" Ross, former chief executive of Broadcom Corp <BRCM.O>, will serve on an interim basis until a permanent chairman has been appointed.

The shares of AMD, which owns a large, but minority stake in the Globalfoundries venture with Abu Dhabi investors Advanced Technology Investment Corp, fell 2 percent to $4.51 on the New York Stock Exchange.

(Additional reporting by Franklin Paul in New York; editing by Gerald E. McCormick and Andre Grenon)