Shares of

Vitesse Semiconductor

(VTSS)

plunged in late trading Tuesday after the chip company said three of its top executives have been placed on leave amid a probe into stock option grants.

The company's board formed a committee of independent directors to conduct an investigation into the timing of the stock option grants. Chief Executive Louis Tomasetta, Chief Financial Officer Yatin Mody and Executive Vice President Eugene Hovanec have each been put on leave. Vitesse named Chris Gardner, the general manager of its network products divisions, acting president and CEO. The move comes after a

Wall Street Journal

article last week raised questions about options pricing and possible backdating of the grants to take advantage of profit potential. Vitesse shares -- which were halted for trading during the regular session Tuesday -- tumbled 80 cents, or 26%, to $2.31 after hours.

Shares of

Cymer

(CYMI)

jumped after the company's first-quarter earnings per share beat Wall Street's estimate by a dime. The company, a maker of laser light sources used by chipmakers, posted earnings of $20.6 million, or 52 cents a share, on revenue of $127.1 million. Analysts polled by Thomson First Call expected earnings of 42 cents on sales of $120.4 million. Last year, first-quarter earnings totaled $5.4 million, or 14 cents a share, on revenue of $84.8 million. The company's gross margin for the most recent quarter totaled 46%, above its guidance of 44% to 45%.

For the second quarter, Cymer predicts a gross margin of 48% to 49%. The company anticipates 5% to 10% revenue growth over the first quarter, implying a top line of $133.5 million to $140 million. Analysts have an average projection for second-quarter revenue of $128.4 million. Cymer shares advanced $3.65, or 7.4%, to $53.10 in after-hours trading.

Illumina

(ILMN) - Get Report

shares rose after the biotech company's first-quarter results and guidance beat Wall Street's projections. The company reported a loss of $104,000, or less than 1 cent a share, narrowed from a year-earlier loss of $1.2 million, or 3 cents a share. Excluding stock-option costs, the company would have posted earnings of $3 million, or 7 cents a share. Revenue jumped to $29.1 million from $15.1 million. Analysts were looking for the company to post earnings of 1 cent a share, before stock options, on $23.8 million in revenue.

For the second quarter, Illumina predicts earnings of 7 cents to 9 cents a share, before items, and revenue of $31 million to $33 million. Analysts project earnings of 3 cents a share and revenue of $28 million. For the full year, the company sees earnings, before items, of 23 cents to 38 cents a share, and revenue of $130 million and $140 million. Wall Street targets earnings of 20 cents a share and revenue of $117 million. Shares gained $2.77, or 11%, to $28.52.

Standard Microsystems

( SMSC) slid after the integrated circuits company reported lower-than-expected fourth-quarter earnings. The company posted earnings of $3.8 million, or 16 cents a share, reversing a year-earlier loss of $2.8 million, or 15 cents a share. Excluding charges, earnings totaled $6.3 million, or 27 cents a share, missing analysts' projection of 31 cents. Revenue for the quarter ended Feb. 28 increased 54% over last year to $84.6 million.

For the fiscal first quarter, Standard Microsystems forecast earnings of 23 cents to 27 cents a share, before items. The company predicts revenue of $82 million to $85 million. Shares declined $1.34, or 5.2%, to $24.60.

Shares of

PLX Technology

(PLXT)

rose after the semiconductor company beat Wall Street's first-quarter earnings expectations. The company posted pro forma net earnings of $3.1 million, or 11 cents a share. Two analysts polled by First Call had an average estimate for earnings of 1 cent a share. Last year, comparable earnings were $70,000, or less than 1 cent a share. Excluding a one-time pickup related to a change in revenue recognition, revenue for the first quarter rose 30% to $17.2 million. For the second quarter, PLX sees revenue of $18 million to $19 million, above analysts' prediction of $17.4 million. Shares advanced 72 cents, or 5.2%, to $14.50 in after-hours trading.