Blank-check IPOs have been on the rise recently. There are companies that conduct initial public offerings for the sole purpose of raising capital to acquire other companies. American Apparel (AMEX: APP) recently went public in this manner.

Historically, Nasdaq listing standards have barred these companies from the exchange, which has been a big boon to the otherwise-struggling AMEX. Now the Nasdaq is proposing a new rule to the SEC that would allow SPACs to list on its exchange.

In the press release announcing the plan, Nasdaq Senior Vice President Bob McCooey said that "Acquisition vehicles are an increasingly common capital-raising device. We believe that listing them on Nasdaq, subject to these important investor protections, will benefit investors and issuers alike."

Maybe this is the right move, but it's interesting that Nasdaq was willing to stand by its principled objection to these entities until the amount of money they raise (and fees/trading volume they can generate) grew too big to ignore.

But I still think investors should be very skeptical of investing in these situations. How exactly do you research an investment in a company when you don't yet know what the business model is?