Computer Associates has licensed The SCO Group's Intellectual Property Licence for Linux.
Two other companies, natural gas supplier Questar and manufacturer Leggett & Platt have also signed up, bringing the total number of publicly announced licensees to four.
SCO maintains that the Linux operating system contains numerous violations of its intellectual property, and in August began offering the IP Licence for Linux to select companies, saying that they could avert the risk of future litigation by paying $699 for each of their computer processors running Linux.
On Monday, SCO revealed that EV1Servers.Net, the hosting division of Houston's Everyones Internet, had signed up for the licence.
Computer Associates was one of three companies named as IP Licence for Linux licensees in a letter written amonth ago by SCO's attorney, Mark J Heiss of the firm Boies, Schiller & Flexner, and addressed to David R Marriott of the firm Cravath Swaine & Moore, who is representing IBM in a lawsuit between the two companies.
The letter was submitted into evidence by IBM and published on the Groklaw.net website.
Yesterday, SCO chief financial officer Bob Bench confirmed that the three companies were licensees, and claimed that his company had now signed up somewhere between 10 and 50 IP Licence for Linux customers.
The company's SCOsource programme, which seeks licensing fees for SCO's intellectual property, booked $20,000 in revenue for its most recent quarter, Bench said, all of it from sales of the IP Licence for Linux.
Bench could not predict how much SCO expected to make from the licences during its next quarter, however. "We have many companies that we're talking to right now. We don't know how quickly they will move."
Questar said that its decision to purchase the IP Licence for Linux was a matter of simple economics.
"Our usage is so small and isolated that's why we went ahead and signed the contract.," said spokesman Chad Jones. "This was small enough that we made a business decision based on the modest cost of SCO's claim that it was in our interest to settle rather than litigate this thing."
Observers were puzzled about Computer Associates' decision to purchase the licence, suggesting that by supporting SCO, the company might hurt its image as a supporter of Linux.
"What were they thinking?" said Bruce Perens, one of the founders of the Open Source Initiative. "I think this sends a very strange message and I'd like to hear a real explanation out of CA."
Sageza Group analyst Charles King said it made little sense for any company to purchase SCO's licence.
"The intellectual property that SCO claims has still not been proven or upheld in court, so what are you buying? As far as I can see, it's the equivalent of giving the neighborhood bully 25 cents so he doesn't steal your lunch next week."
Computer Associates declined to comment on this story. Representatives from Leggett & Platt did not return calls seeking comment.
Robert McMillan writes for IDG News Service