So much for retirement. Microsoft founder Bill Gates is reportedly creating a new company to coordinate business for the software giant and his philanthropic Gates Foundation.

The mysteriously dubbed bgC3 LLC, first reported yesterday by the blog TechFlash, will apparently be a think tank for science and tech innovations. The "C" in the name stands for "catalyst," not "company," an unidentified source told TechFlash.

Gates, who stepped down from his day-to-day role at Microsoft in June, has a high-tech shop outside Seattle for bgC3, outfitted with his company's Surface touch-table computer. But TechFlash speculates bgC3 won't be a new, giant enterprise: A letter a Gates rep wrote to a city official in Kirkland, Wash., where the office is housed, said occupancy would be limited to 40 to 60 people — far fewer than the thousands of worker bees on the sprawling Microsoft campus in nearby Redmond.

The Wall Street Journal Business Technology Blog takes a more cynical view of bgC3, describing it as "neutral ground" where Gates can discuss Microsoft or the foundation (he can't conduct business for one at the other's office) and as "a legal entity" where he can pay the handlers who "coordinate and protect [his] life."

TechFlash's analysis sounds sexier to us, but we'll have to wait until Gates decides to spill the beans on his next trick. In the meantime, we're intrigued by the science his foundation is backing: Grants of $100,000 announced yesterday will fund research into whether fetuses can be immunized before birth; whether the use of a bacteria can limit tropical dengue fever in disease-spreading mosquitoes; and if introducing HIV-fighting molecules into "good" bacteria found in the vagina can prevent infection of the AIDS-causing virus. 

(Updated at 4:10 p.m. with information on new Gates Foundation grants.)

(Image of Bill Gates/Microsoft)