Small-cap stocks fell in tight formation with the major indices Friday, fueled in part by

Quantum Fuel Systems Technologies Worldwide's

(QTWW)

sharp decline.

The Irvine, Calif., auto-parts maker plummeted 18% to $1.71 after saying it will sell 12.5 million shares to institutional investors for $1.50 a pop -- a 28% discount to its latest close. Investors will also get warrants to buy another 15 million shares with an exercise price of $2.09 apiece, including around 2.5 million for existing shareholders in exchange for the waiving of certain rights granted in an October private placement.

Metalico

(MEA)

also fell on a private placement to institutional investors. The Cranford, N.J., scrap-metal processor will sell some 5.2 million shares of newly minted stock at $7 each to fund takeouts of two scrap-metal recycling companies, as well as for general corporate purposes. Shares slid 64 cents, or 7.8%, to $7.53.

Dropping on negative analyst research, meanwhile, was

Inphonic

( INPC), an online seller of wireless services. Deutsche Bank lowered the Washington, D.C., company to hold from buy, cutting 2007 expectations for the firm and slicing its per-share price target by $10 to $6. Shares tumbled 14% to $5.10.

The Russell 2000 slid along with components Quantum and Inphonic, losing 0.9% to 832.55 in recent trading. The S&P SmallCap 600 gave up 1% at 432.35

On the lonelier upswing, however, was China's

Sohu.com

(SOHU) - Get Report

. The stock rose 7.3% at $29.50 after a Credit Suisse analyst upped the company to outperform -- citing, among other things, the success of one of the site's multiplayer games -- and medical-device maker

DJO

( DJO) was also bouncing. Shares of the Vista, Calif., firm added 4% after MMI Investments disclosed it has taken a 9.4% stake in the company, having bought some 2.2 million DJO shares over the past couple of months.

Finally, hot-dog chain

Nathan's Famous

(NATH) - Get Report

nearly doubled its fourth-quarter continuing-operations income from last year to 19 cents a share. Revenue for the quarter ended March 25 climbed 12% to $9.9 million. Shares gained 4.8% to $15.71.