Today's Early Winners and Losers

Shares of Plexus(PLXS Quote) surged in after-hours trading Thursday after the electronics manufacturing services company beat Wall Street's second-quarter earnings expectations and issued higher-than-anticipated guidance.

Plexus reported income of $18.5 million, or 40 cents a share, compared with a charge-laden loss of $4.5 million, or 10 cents a share, a year earlier. Revenue increased 11% over a year ago to $337.9 million. Analysts polled by Thomson First Call were looking for earnings of 34 cents a share in the latest quarter, with revenue of $340.9 million.

For the third quarter, Plexus forecast earnings of 50 cents to 55 cents a share, before items. Analysts had forecast a much lower 38 cents a share. The company sees revenue of $390 million to $405 million, above Wall Street's target of $367.4 million. Shares jumped $5.32, or 14%, to $44.59 in after-hours trading.

Intuitive Surgical(ISRG Quote) shares gained after the maker of surgical robotics posted first-quarter results that easily beat analyst projections. The company's earnings rose to $14.5 million, or 38 cents a share, from $9.1 million, or 25 cents a share, a year ago.

Excluding stock-option expenses, earnings were $17.5 million, or 46 cents a share, more than double First Call's analyst estimate of 20 cents. The company's revenue jumped 86% to $77.3 million, driven by increased sales of its da Vinci Surgical System. Analysts had forecast revenue of $62.8 million. Shares leaped $14.47, or 14%, to $117.64 in late trading.

Shares of Harmonic(HLIT Quote) fell after the communications-equipment maker posted a first-quarter loss that was worse than Wall Street's projection. The company said it swung to a loss of $5.1 million, or 7 cents a share, from a profit of $1.7 million, or 2 cents a share, a year ago.

Excluding items, the loss totaled 4 cents a share, wider than analysts' mean estimate of 1 cent. Sales slipped to $56.2 million from $63.7 million a year earlier, and came in shy of Wall Street's target of $58.2 million.