So, you say you want to buy into the next hot initial public offering and can't wait for Facebook to go public.

Take a deep breath. It takes a good bit of work -- and cash -- to get directly into an IPO. And there's no guarantee, especially right now, that you'll make the quick killing you think you will.

Initial public offerings behave fairly consistently, and if you don't know the likely patterns, you could find yourself losing money. IPOs also can generate gobs of unwarranted hype.

Facebook, reporters breathlessly note, may go public next year with a market capitalization of $100 billion. And everyone -- yourself included -- wants in on the deal. Maybe Facebook will prove to be worth more than $100 billion, which would put it in the same league as ConocoPhillips (COP, news), PepsiCo (PEP, news) and Citigroup (C, news). But maybe not.

The problem right now is that the stock market is stressed out over the economy and the battle over the government debt ceiling. The Dow Jones Industrial Average ($INDU) dropped more than 7% after peaking on April 29; the loss has been trimmed to just 2%. And there's been some disappointment with the performances of stocks that have gone public in recent weeks, especially Chinese Internet stocks and Internet radio company Pandora Media (P, news).

But hopes are high for Dunkin' Brands, owner of the Dunkin' Donuts and Baskin-Robbins chains. The company plans to sell 22.5 billion shares at $19 a share, above its projected range of $16 to $18. Trading was to start on Wednesday.

This is a big change from just last month when LinkedIn (LNKD, news), the business-related social-networking site, debuted in a spectacular way. The demand for shares was huge when the company went public on May 19 at $45. The stock opened for trading at $83 and hit $122.91, before ending the day at $94.20. That translated into a market capitalization of $6.3 billion.

That grabbed a lot of attention and prompted speculation that 2011 was shaping up as the year of the great social-networking IPO bubble.

Image: Charlie Blaine

Charlie Blaine

But, as often happens, LinkedIn fell back rather quickly. It hit a bottom on June 20 at $63.71. Or course, that was still up 41.6%. But it has taken off again. With Tuesday's close of $102.52, that's a 60.9% gain from that June 20 low, and it gives the company a market capitalization of $9.5 billion.

Pandora has had a different experience. Its shares went public at $16 on June 14, opened for trading the next morning at $20 and hit $26 before falling back to close at $17.14. It has struggled since, in large part because the company isn't yet profitable. The shares closed at $17.28 on Tuesday.

Pandora isn't alone. Zipcar (ZIP, news), the car-sharing company, went public on April 13 at $18. It opened for trading the next day at $30, reached $31.50 but finished the day at $28. It's now at $22.66, up 25.9% from the IPO price, but down 19.1% from the first-day close.

3 ways to get in

So, how do you play this game? Here are some questions and answers about the rules, as we understand them.

Can you get in at the IPO price? Unfortunately, this game is basically rigged against the little guy. The underwriters -- such as Morgan Stanley, Goldman Sachs and Merrill Lynch -- don't want to sell the shares to average investors. They want their big, rich customers to get them. That can include hedge funds, pension funds, takeover speculators, movie stars and corporate moguls. So, basically, if you want in, you need to have a lot of money. And then you have to call the underwriter and demand to be let in.

You can also try to get some shares in the nonpublic market via, say, SecondMarket. Again, this is a game for high-net-worth folks. So, if you're a small investor, good luck.

What if you can't get in the door with the underwriters? You can buy into mutual funds that specialize in investing in IPOs. Renaissance Capital, which tracks IPOs as a business, sponsors the Global IPO Plus Aftermarket (IPOSX), which buys shares of companies after their IPOs. The fund has not been a huge winner, though. It has produced a total return of about 2.6% this year and is basically flat over the past 10 years.

Or you can wait until after the initial euphoria subsides. For many investors, this is the easiest and possibly the cheapest way to go.

As noted with LinkedIn and Pandora, IPOs often jump on the first day of trading and, once the hype fades, fall back to a level that makes more economic sense.

How long to wait is an important question. Some think two years will tell you if the company is real. If you'd waited that long with Google (GOOG, news), which went public in August 2004, you'd have signed away some big profits. Google went public at $85, with the shares opening at $100. By January 2005, the shares were at $200. Less than a year later, the shares had hit $300.

Mind the financial details

The best information to use to decide whether to wait is what's in the prospectus. Look for financial data that show how the company has performed. If the company is already a consistent moneymaker and the price isn't too high (think price-to-earnings ratio), maybe it's worth buying quickly.

Groupon was generating lots of excitement until it said it was going to go public with a $1 billion offering. Then investors found in its registration statement that the company lost $102.7 million in the first quarter and has built up an accumulated deficit of $522 million since its founding. A later amendment showed that two investment vehicles owned by Groupon founder Eric Lefkofsky and his wife reaped $386 million by redeeming shares in the company. They bought the shares, The Wall Street Journal noted, for $546. ("Yes, you read that right," the Journal noted.) Still, the company has seen staggering growth. Subscribers have jumped from 1.8 million in 2009 to 83 million at the end of March.

So, while there's a lot of excitement about the company, it may take a while for the IPO to come to market and get properly priced.

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So, should you chase after Facebook? You need some numbers. So far, there aren't any. The Wall Street Journal said the company reportedly will show $2 billion in profit after interest, taxes, depreciation and amortization. That's an impressive number, suggesting revenue of at least $4 billion.

Because Facebook lives mainly on advertising, a big question to consider is response to the ads on Facebook. A hotly contested report by Forrester Research suggests that the response to the ads on Facebook -- whether Facebook users will buy stuff on the site -- may be lower than expected.

So wait for the documents, and let the numbers decide.