Lance Armstrong is facing a $12m (£7.6m) lawsuit after SCA promotions announced its intention to recoup the bonuses paid to the Texan when he won his fourth, fifth and sixth Tour de France titles.
Armstrong admitted he used performance-enhancing drugs during each of his seven Tour victories in an interview with Oprah Winfrey last month.
And SCA lawyer Jeff Dorough told BBC Sport: "I can now confirm we intend to file a suit against Mr Armstrong first thing on Thursday morning."
SCA initially refused to pay out the money covering the bonus of £5m for Armstrong's sixth Tour win in 2004 after they disputed the Texan was riding clean.
Armstrong took the company to an arbitration hearing in Dallas in 2005 and won because the contract between the parties stipulated he would earn the bonus if he was the "official winner" of the 2004 Tour. Armstrong was awarded $2.5m in damages and costs.
However Armstrong's attorney Tim Herman has already said his client does not intend to repay the money.
"My only point is no athlete ever, to my understanding, has ever gone back and paid back his compensation," Herman told USA Today earlier this week.
The Sunday Times are already suing Armstrong for £1m over the settlement of a libel action.
Armstrong, who has been stripped of his seven Tour titles between 1999 and 2005, received £300,000 from the newspaper in 2006 as payment towards legal fees regarding an article written by David Walsh questioned the validity of his success after he had survived testicular cancer.
"It is clear that the proceedings were baseless and fraudulent," said a letter from lawyers representing The Sunday Times in December.