NEW YORK (CNNMoney.com) -- Stocks are stuck in a rut, and that's taking a toll on the market for companies going public.

Private-equity backed GNC Corp. and Internet domain registration company Go Daddy Group both withdrew their initial public offerings this past week, citing poor market conditions.

The Nasdaq has lost nearly 7 percent so far this year.

Just halfway into the third quarter, some 15 companies have withdrawn or postponed their plans to go public, according to deal tracker Dealogic. That many deals were withdrawn or postponed in the entire second quarter.

The Nasdaq composite (Charts) dove in May, and has been on a downward spiral ever since. The tech-heavy index, considered to be a barometer of the IPO market, has lost nearly 7 percent so far this year. (See chart)

This week, only two firms are planning to go public.

InnerWorkings handles printing jobs for corporate clients. The company plans to offer 10.6 million shares - 7.1 million from InnerWorkings and 3.5 million from selling shareholders - priced at between $8 and $9 a share. The company will list on the Nasdaq under the ticker "INWK."

Marathon Acquisition is a so-called blank check company, which means it doesn't have any operating businesses of its own, but instead plans to acquire or merge with other companies.

Marathon plans to offer 37.5 million units, which are expected to price around $8 a share. Each unit represents one share of stock and one warrant. Each warrant allows a holder to purchase a share of stock at $6 a share at a later date. Marathon plans to list on the American Stock Exchange under the symbol "MAQ.U."

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