https://abcnews.go.com/Business/facebook-ipo-tough-investors/story?id=16307075

Investors who "like" Facebook may now be able to put their money where their clicks are.

Most of the large online brokerage firms, including E-Trade, Fidelity and Charles Schwab, are allowing customers to request shares of the Facebook initial public offering. It's the latest phase in kicking off what's expected to be the largest technology IPO next week.

Given the large degree of attention on this IPO, though, investors shouldn't expect to actually get shares or make money on them. "I anticipate there to be many orders relative to the number of shares available to allocate," says Jay Ritter, professor of finance at the University of Florida.

Some key caveats and risks investors interested in getting Facebook shares from their brokerages should keep in mind include:

•Rules limit who is eligible.

Most online brokerage firms reserve the right to limit who gets Facebook shares. Fidelity investors must have $500,000 in qualified balances at the brokerage or trade 36 times a year or more to be considered, the company says. Schwab is telling customers to call their representatives to see if they are eligible.

Kimihiro Hoshino/AFP/Getty Images
Facebook CEO Mark Zuckerberg delivering a... View Full Size

Kimihiro Hoshino/AFP/Getty Images
Facebook CEO Mark Zuckerberg delivering a keynote during the Facebook f8 Developer Conference at the San Francisco Design Center in this Sept. 22, 2011 file photo.TD Ameritrade is allowing investors to participate if their account is valued at $250,000 or more or they have completed at least 30 trades in the past three months.

•No guarantee of shares even for qualified investors.

While investors might request shares, they might not get any or as many as they'd like, Ritter says.

•Stipulations to ownership.

Most brokerages don't require investors to hold IPO shares for a set number of days but may punish investors who don't. E-Trade recommends investors hold IPO shares for at least 30 days and may exclude investors who don't from future deals, says the company's website.

Fidelity investors may be precluded from future IPOs if they sell in fewer than 15 days.