UPDATE 5-SandRidge Permian unchanged, Carbonite rises

* SandRidge Permian Trust shares unchanged from IPO price

* Carbonite shares up 23.5 percent

* Only two of 12 IPOs scheduled this week have priced

* S&P down 13.9 percent since early May (Adds details on another SandRidge royalty trust, updates shares)

By Clare Baldwin

NEW YORK, Aug 11 (Reuters) - The shares of SandRidge Permian Trust (PER.N), an oil and gas royalty trust, were unchanged in their stock market debut after tumultuous markets curtailed most initial public offerings scheduled for this week.

The IPO raised $540 million -- 14 percent less than anticipated -- but still got done, reinforcing the idea that investors are strongly interested in yield, experts said.

"People are thinking seriously about getting out of U.S. government bonds ... SandRidge is not an equal in that regard, but it does have a very nice yield," said David Menlow, president of IPOfinancial.com.

SandRidge Permian Trust is promising investors a cut of its proceeds from selling oil, natural gas and natural gas liquids.

On Wednesday, the trust raised $540 million by selling 30 million units for $18 each -- less than the 31.5 million units it planned to sell for $19 to $21 each. The shares ended at $18 on Thursday on the New York Stock Exchange.

SandRidge has 509 producing wells, including 13 that are not complete, and plans to drill another 888 development wells. The wells are in the Permian Basin in western Texas.

As natural gas prices remain low and drilling costs remain high, smaller oil and gas producers are searching out new sources of funding. Joint ventures and asset sales are one option; IPOs are another.[ID:nN1E75R1EE]

In April, SandRidge did an similar IPO of wells in Oklahoma that were listed as SandRidge Mississippian Trust I (SDT.N). Common units of that trust closed at $24.48, or 16.6 percent above their $21 IPO price.

Separately, Web-based computer backup company Carbonite Inc (CARB.O), which raised $62.5 million in its IPO and also began trading on Thursday, ended trading on the Nasdaq at $12.35, up 23.5 percent from its IPO price of $10. The company priced its IPO at the bottom of a lowered price range, and raised about 38 percent less than planned.

Concerns about the U.S. economy and the European debt crisis have helped push the S&P 500 index .SPX down about 13.9 percent from a peak at the start of May. Of the 12 IPOs expected this week, only two have priced.

Underwriters on the SandRidge IPO were led by Morgan Stanley, Raymond James, RBC Capital Markets and Wells Fargo Securities.

Bank of America Merrill Lynch and JPMorgan lead the underwriters on Carbonite. (Editing by Gerald E. McCormick, John Wallace, Robert MacMillan, Andre Grenon and Steve Orlofsky)