SAN FRANCISCO — Nasdaq has long been known as the “tech-heavy” stock exchange, where some of Silicon Valley’s best-known companies have gone to sell shares.

Now, as it faces stiff competition from rival exchanges to lure the next hot IPO, it’s reaching out to business startups before they go public.

New York-based Nasdaq, through an affiliated foundation, was opening what it calls an “Entrepreneurial Center” Thursday in a trendy commercial district south of San Francisco’s Market Street. It’s promising business training, mentoring and networking opportunities for early stage startup founders – maybe even the next Mark Zuckerberg or Larry Page.

Nasdaq executives say they have a long tradition of working with young companies, and the new center is open to entrepreneurs in other sectors besides tech. Still, it’s no coincidence the center’s in a region rife with new tech startups. Facebook, Google and Apple are all traded on Nasdaq.

The move comes as Nasdaq’s chief rival, the New York Stock Exchange, has increased its outreach to the tech sector in recent years and has lured some high-profile startups like Twitter, which held its initial public offering on the NYSE in 2013. Twitter’s decision to list on the NYSE came after Facebook’s debut on Nasdaq in May 2012 was marred by technical glitches that tarnished the exchange’s reputation.

Silicon Valley is home to a umber of tech “incubators” and other programs that support new startups, sometimes in exchange for equity.