(Bloomberg) Companies in the U.S. are raising less this year from initial public offerings than any time in at least a decade compared with the amount they filed to sell.

IPOs on the New York Stock Exchange and the Nasdaq Stock Market have raised $19.1 billion in 2010, while companies from Nielsen Holdings BV and Demand Media Inc. to General Motors Co. filed with the Securities and Exchange Commission to sell $48.9 billion in shares, according to data compiled by Bloomberg. That's the widest gap since at least 1999, the data show.

More than half the companies that submitted plans for IPOs in 2010 have yet to complete them after 61% of this year's offerings left buyers with losses. While 68% of the deals raised less than sought, private equity funds and venture capital firms are still seeking to sell holdings after the financial crisis blocked them from exiting investments.

"It's going to be tough for awhile," said Christopher Turner, head of capital markets at New York-based private equity firm Warburg Pincus LLC, which oversees about $30 billion. "You're going to see a continuing big pipeline relative to the pace of execution. Investors have lost money in IPOs they've bought, and they're now looking at any pricing range pretty askance and starting by asking for a steep discount."

Companies controlled by leveraged buyout funds account for 42 of the 170 that registered for IPOs or updated their filings in the last two years, according to a note last week from Greenwich, Connecticut-based Renaissance Capital LLC, which has studied initial offerings since 1991.

Private Equity IPOs

The number of IPOs that have yet to be completed has grown 81% from a year ago as investors shunned offerings backed by private equity firms, which take controlling stakes in companies and use borrowed money to finance most of the acquisition.

The 19 initial sales from U.S. companies led by LBO firms have lost 1.9% of their value in the first month of trading in 2010, after averaging gains every year since at least 2001, data compiled by Bloomberg and Renaissance show.

Private equity owners are relying on IPOs to help pare debt and reduce their stakes a year after buyout firms returned less money to their clients than any time in the past decade, data compiled by London-based Preqin Ltd. show.

The funds, which usually have a lifespan of about 10 years, spend three to six years making investments and then seek to reap profits from those deals in the remaining period.

Broken Model

"There's a lot of private equity funds trying to sell companies to show people that the LBO model isn't broken," said Charles Bobrinskoy, vice chairman at Chicago-based Ariel Investments LLC, which oversees about $5 billion.

Nielsen Holdings, the New York-based television-audience rating company owned by KKR & Co. and Blackstone Group LP of New York, Washington-based Carlyle Group and Thomas H. Lee Partners LP in Boston, is seeking to raise $2 billion to help pay down its $8.4 billion in debt, SEC filings show.

HCA Inc., the Nashville, Tennessee-based hospital chain bought four years ago in a $33 billion LBO led by KKR and Boston-based Bain Capital LLC, plans to sell $4.6 billion of shares, according to a regulatory filing. Toys "R" Us Inc., the toy-store chain acquired by KKR, Bain and Vornado Realty Trust of New York in 2005, is seeking to raise $800 million.

While HCA and Wayne, New Jersey-based Toys "R" Us filed with the SEC in May and Nielsen followed in June, none have set a date for their offerings. Concern that the economic recovery is deteriorating helped send the Standard & Poor's 500 Index down as much as 16% from its 2010 high.

'Hasn't Picked Up'

"The economy hasn't picked up as quickly as was expected, which has affected the plans of a lot of companies on file," said Frank Maturo, Bank of America Corp.'s New York-based co-head of equity capital markets for the Americas. "Some deals are going to get pushed to later in 2010 or even 2011."

A fourfold increase in venture capital-backed companies that have registered for IPOs to 42 from nine a year ago may signal a willingness to accept lower valuations in order to go public, according to a note last week from Renaissance.

Demand Media, the Santa Monica, Calif.-based developer of applications for social-media websites, filed last month to raise as much as $125 million. The creator of content for sites on fitness and travel is backed by Palo Alto, Calif.-based Oak Investment Partners and Spectrum Equity Investors in Menlo Park, Calif.

'Look for Exits'

SciQuest Inc., the Cary, N.C.-based Internet software company that provides on-demand services in 16 countries, will seek to raise $69 million this week. Menlo Park- based Trinity Ventures owns a majority stake in SciQuest.

This month's offerings come after the S&P 500 rebounded 11% from its 2010 low on July 2. Beijing-based SouFun Holdings Ltd. rallied 73% after pricing the first U.S. IPO in three weeks on September 16.

Companies that complete sales this quarter will avoid competing with GM for capital. The Detroit-based automaker may seek to raise $8 billion to $10 billion in November, a smaller sale than GM originally targeted, two people familiar with the offering said today.

GM had been considering a deal as large at $16 billion, a person familiar with the plan said last month. A $10 billion initial sale would still be the largest in the U.S. since San Francisco-based Visa Inc.'s record $19.7 billion offering in March 2008, data compiled by Bloomberg show.

"A number of venture capital and private equity portfolios are getting pretty late in their life cycles and they need to look for exits," said Joseph Garner, director of research at Lancaster, Pa.-based Emerald Asset Management Inc., which oversees about $2 billion. "The IPO window was closed and now it appears to have reopened, and it's uncertain how long it will remain open. If going public is in your plans, there may be no better time than the present."