Corrected: Pressure grows on Sacyr to sell Eiffage stake

(Corrects spelling of Morrell from Morell in paragraph 3)

By Sonya Dowsett

MADRID (Reuters) - Pressure is mounting on Spain's Sacyr Vallehermoso SVO.MC, already spurned by investors for its sky-high debt and exposure to property, to sell its one third stake in French public works firm Eiffage FOUG.PA.

Shares in the construction company have nearly halved over the past 12 months, underperforming Spain's blue-chip index .IBEX by more than 40 percent during the same period.

"Any company with high debt levels is getting crucified by the market," said Rupert Morrell, fund manager at Premier Asset Management. "You only have to look at the stock to see there's huge pressure there."

A French court is due to rule on Wednesday whether Sacyr should make a forced bid for the rest of Eiffage, at a price valuing the builder of the Sydney Opera house at 12 billion euros ($18.9 billion) -- nearly twice its current market value.

But analysts believe Sacyr will appeal any mandatory bid, prolonging the legal wrangles while it searches for a buyer.

"If they can't get a reasonable price, they will try to stay in their current position, as long as their debt requests from financial institutions are not too aggressive," said a Madrid-based analyst at an international bank.

A Sacyr spokesman declined to comment on what the firm would do if the court ruled in favor of Eiffage's demands Sacyr must make a full bid.