Stocks drifted higher after the close Monday as more companies shuttled in their first-quarter earnings reports.

Wynn Resorts

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, of Las Vegas,

swung

to a first-quarter GAAP-based profit and posted adjusted earnings of 67 cents a share, vs. 3 cents last year. Analysts polled by Thomson Financial were seeking 55 cents a share. Shares were gaining 2.1% to $104 in heavy trading.

Shares of

McDermott International

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jumped 9.4% to $64.60 after the Houston-based energy-services outfit reported that first-quarter income tripled to $158.1 million, or $1.38 a share, on sharply higher revenue of $1.36 billion. Analysts sought profits of 75 cents a share on $1.27 billion in sales.

Elsewhere, online jewelry retailer

Blue Nile

(NILE)

, of Seattle, gained 5.6% to $50.01 after first-quarter earnings totaled 19 cents a share -- a 6-cent jump from last year and 4 cents more than expected.

AmTrust Financial

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, a New York-based insurance broker, was up 5.5% to $13.80 on mounting profits and revenue, and Florida's

WellCare Health Plans

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topped the Street's average profit forecast while boosting its 2007 outlook. Shares added 8.4% to $89.75.

Among Monday's after-hours laggards, however, was

Heelys

( HLYS), maker of children's sneaker-skates. Directors and officers will sell 8 million company shares along with a 1.2-million-share underwriter's option for covering any overallotments. As part of the offering, Capital Southwest Venture is slated to cut its 34.4% stake by more than half. The Dallas-based company

topped first-quarter estimates

, but shares were still plunging 13.3% to $31.50.

Other late movers included tech stocks

Sonus Networks

(SONS)

and

Powerwave Technologies

(PWAV)

.

Sonus, a Westford, Mass., Internet phone-switch maker, initially sank 3.7% on heavy volume after first-quarter sales came in

below consensus

, but shares recently reversed course, rising 3.8% to $7.65. California-based Powerwave, a wireless-equipment maker, posted a first-quarter loss of 20 cents a share (pro forma), which reverses last year's 3-cent profit and falls a nickel under Wall Street projections. Shares slid 6.6% at $6.25.

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