Small-cap stocks joined the broader market on a forward march Tuesday, posting early gains and mostly holding their ground. The Russell 2000 was gaining 1.5% to 710.24, and the S&P SmallCap 600 rose 1.4% to 374.93.

GMH Communities

( GCT), a real estate investment trust based in Newtown Square, Pa., led the charge. Shares rose 55.5% to $8.69 on news that

American Campus Communities

(ACC) - Get American Campus Communities, Inc. Report

would buy GMH for $1.4 billion in cash and stock. American Campus shares, meanwhile, fell 1.5% to $28.

Greeneville, Tenn.'s

Forward Air

(FWRD) - Get Forward Air Corporation Report

, a provider of logistics services to the air freight market, saw shares barrel 13.8% higher to $34.05 on fourth-quarter earnings. The company posted income of $12.4 million, or 43 cents a share, vs. $12.2 million, or 40 cents a share, a year ago, beating the Street's estimate by a nickel, per Thomson Financial.

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Also rallying on earnings was

99 Cents Only Stores

( NDN). Shares of the City of Commerce, Calif., company whose name says it all rocketed 7% to $9.29 after it announced third-quarter earnings following Monday's market close. Profit increased year over year to $9.5 million, or 14 cents a share, from $8.9 million, or 13 cents a share, a year ago. Analysts were seeking 11 cents a share.

Not all stocks performed as valiantly.

Dycom Industries

(DY) - Get Dycom Industries, Inc. Report

last night lowered its outlook for its second quarter of fiscal 2008. The contractor now expects non-GAAP earnings to range from 3 cents to 4 cents a share, which is 11 cents to 12 cents below the low end of its November 2007 guidance. Analysts are looking for 20 cents a share. Friedman Billings brought more pain by downgrading Dycom to market perform from outperform this morning. The Palm Beach Gardens, Fla.-based company saw shares retreat 31.4% to $15.99.

Zoltek

(ZOLT)

shares likewise fell back, slipping 19.6% to $26.23. The St. Louis maker of carbon and technical fibers posted first-quarter earnings of $2.6 million, or 8 cents a share, vs. a loss of $5.7 million, or 22 cents a share, in the year-ago quarter. Excluding charges, fourth-quarter EPS were 14 cents, compared with 11 cents a year ago. Analysts, who do not typically include charges in their estimates, are forecasting 24 cents a share.