NBC said Thursday that it has acquired a minority stake in online film and music trading game the Hollywood Stock Exchange.

Although both companies declined to disclose the multimillion-dollar figure invested, NBC said it will promote the site across its Web ventures, which include portal Snap.com, NBC.com and MSNBC.com.

NBC will, for example, create an Entertainment Trading Center for Snap.com and Access Hollywood.com.

HSX will also receive ad time on NBC, beginning later this month.

In return, Santa Monica-based HSX will create content for the Web sites. HSX already supplies content to syndie entertainment mag “Access Hollywood,” including a “Hollywood Stock Exchange Market Update” segment in which HSX co-founder Max Keiser discusses trends and topics based on the market action on the exchange.

On the HSX site, nearly 800,000 Netizens buy and sell virtual stock in celebrities, movies and music properties online using so-called Hollywood dollars.

“We couldn’t be more pleased about this transaction, which continues to demonstrate just how NBC broadcast television and the Internet can work together in complementary ways,” said Marty Yudkovitz, prexy of NBC Interactive.