Nike, which had been an Armstrong supporter since 1996, was the first to announce it would be ending its sponsorship after the release of an extensive report from the U.S. Anti-Doping Agency. The company found the more than 1, 000 pages of evidence too damning to ignore.
"Due to the seemingly insurmountable evidence that Lance Armstrong participated in doping and misled Nike for more than a decade, it is with great sadness that we have terminated our contract with him. Nike does not condone the use of illegal performance-enhancing drugs in any manner, " the company said.
While Nike was the largest supporter to cut ties with Armstrong, one of the smallest, Honey Stinger, a Colorado-based maker of honey-based nutrition foods, also moved quickly to terminate its relationship, effective immediately.
"We are in the process of removing Lance Armstrong's image and endorsement from our product packaging, " Honey Stinger said in a statement. "While this presents short-term challenges, we look forward to growing our brand and offering our customers the best products possible."
Bicycle-maker Trek said Wednesday it was "disappointed by the findings and conclusions in the USADA report" and "given the determinations of the report, Trek today is terminating our long-term relationship with Lance Armstrong."
Easton-Bell Sports, makers of Giro brand bicycle helmets said they "would not be continuing (its) sponsorship of Lance Armstrong going forward."
24 Hour Fitness, operator of a national chain of health clubs, said it "does not condone the use of performance-enhancing drugs or procedures. Given the evidence surrounding Lance Armstrong's alleged actions, we have determined that our business relationship with Armstrong no longer aligns with our company's mission and values. Over the coming weeks, we plan to remove the Lance Armstrong brand from our six co-branded fitness clubs."
Some sponsors chose not to terminate its relationship immediately. Instead, they simply announced they would not be renewing their current contract with Armstrong.
Taking that approach was Anheuser-Busch, for which Armstrong endorsed the Michelob Ultra brand. Paul Chibe, Vice President of U.S. Marketing issued a statement that said: "We have decided not to renew our relationship with Lance Armstrong when our current contract expires at the end of 2012. We will continue to support the Livestrong Foundation and its cycling and running events." (Read More: Armstrong Leaves Livestrong on a Rocky Road )
One company that declined to discuss the timing of its decision to disassociate with Armstrong was RadioShack . The company acknowledged a "multi-year agreement" with Armstrong that began in July 2009, but said simply: "Radioshack has no current obligations with Lance Armstrong." It would decline to elaborate any further.
While losing eight sponsors in less than 12 hours is a stunning fall from grace, the damage could get worse for the disgraced icon. Another Armstrong sponsor, sunglass maker Oakley, has left its options wide open regarding its relationship with the retired cyclist.
"Oakley does not approve in any way the use of illegal substances for enhancing performance in sports. Our policy with our athletes is to support them until proven guilty by the highest governing body of sport or court of law. We are reviewing the extensive report from the USADA, as well as our relationship with Lance, and will await final decision-making by the International Cycling Union, " the company said, in a statement.
-By Tom Rotunno, CNBC Senior EditorQuestions? Comments? Email us at firstname.lastname@example.org. Follow Tom Rotunno on Twitter @tomrotunno.