Small-cap stocks underperformed the rest of the market for the second straight session Tuesday, even in the wake of soaring stocks like

Steak n Shake

( SNS).

The Indianapolis-based restaurant chain surged 17.6% to $17.38 after an investor consortium that includes HBK Investments and Indy Investments disclosed that it had taken a 9.5% stake in the company, or some 2.7 million shares.

The stock helped to support both the Russell 2000 and the S&P SmallCap 600 along with California-based footwear maker

K-Swiss

( KSWS), which tacked on 1.8% to $28.09 after Brean Murray started coverage of the stock with a buy rating.

The Russell 2000 was hugging the flat line, while the S&P SmallCap was off 0.4%.

Among other gainers was

Cell Therapeutics

(CTIC) - Get Report

. Shares jumped 7.7% to $3.20 on word of positive results from preclinical studies of a drug in its pipeline, pixantrone, the findings of which have been published in

Investigational New Drugs

. The compound was shown to induce "minimal or no significant cardiotoxicity," while existing treatments doxorubicin and mitoxantrone resulted in "significant cardiac damage." Cell Therapeutics expects to have its own interim results from a randomized phase II/III clinical trial of pixantrone later this year.

On the flip side,

LivePerson

(LPSN) - Get Report

, a purveyor of hosted customer-service software, slid 16.1% after agreeing to buy Israel-based Kasamba, which provides expert advice online, for $40 million in cash and stock. New York-based LivePerson expects the transaction to cut 1 cent to 2 cents off per-share earnings in the fourth quarter. The deal should close in about 90 days. Shares were trading at $5.20.

Elsewhere, financial-information Web site

Bankrate

(RATE)

dropped after Oppenheimer began coverage of the stock with a neutral rating. The analyst cited limited upside potential, given the current per-share price. Shares were shedding $1.14, or 2.3%, to $47.86.