HOUSTON, May 8 (Reuters) - A U.S. court of appeals has granted Venezuela a temporary stay preventing six companies from joining a proposed court auction of shares in a Citgo Petroleum parent to enforce judgments for past expropriation of assets. The companies had won conditional attachments to a federal case in which the judge has approved a process to auction the shares to pay a $970 million judgment won by miner Crystallex. The six hold arbitration awards or judgments that total about $2.6 billion and wanted those awards to be included in the auction. The proposed auction, which could break up the seventh largest U.S. refiner to pay creditors, took a giant step forward last month with a greenlight from the U.S. Treasury. Washington has since recognized the opposition-led congress as the entity controlling the refining subsidiary, extending protection to prevent its breakup at the hands of Venezuela creditors.

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