Two more county-based technology firms whose stock...

Two more county-based technology firms whose stock has soared recently are Silicon Systems (SLCN-OTC) and Western Digital (WDC-ASE).

But it is investors’ growing awareness of the companies rather than any major change in business that has sparked the move, according to Jay Vleeschhouwer, a technology industry analyst at the Los Angeles investment firm of L.H. Friend & Co.

“Wall Street noticed these companies. . . . And then there was a surge in buying orders,” said Vleeschhouwer, who follows both companies.

Stock in Silicon Systems, a Tustin-based maker of integrated circuits, has gained 55% since it closed Dec. 4 at $6.125 per share. The stock closed Friday at $9.50, up $2.125 for the week, but still well below its 12-month high of $15.25.

“Silicon Systems was one of the names on everyone’s wish list,” Vleeschhouwer said.

He said if the stock market continues its recent strength, Silicon Systems stock could continue to gain ground. The Dow Jones Industrial Average--a measure of the stock prices of the largest industrial corporations--advanced 5.8%, or 108.26 points, last week to close Friday at 1975.30, up 11.5% since Dec. 4.

Vleeschhouwer noted that Silicon Systems might earn up to $6.8 million, or $1 per share, in its fiscal 1988, which ends in September.

For fiscal 1987, Silicon Systems earned $2.8 million, or 40 cents a share.

Stock in Western Digital has also recovered some of the value it lost following the 508-point collapse of the Dow Industrial Average on Oct. 19.

Western Digital, a computer-components maker, closed Friday at $15.75, up $1.875 for the week and up 31% since Dec. 4, when it closed at its 12-month low of $12 per share.

Vleeschhouwer said that investors have taken notice of Western Digital’s consistent performance and that some analysts have recently increased earnings estimates for the company.

He said he expects the company to earn 46 cents a share, or $11.8 million, in the company’s fiscal 1988 second quarter, which ends this month.

In the second quarter of 1987, the company earned $10.4 million before it added an extraordinary item worth $1.3 million.

Vleeschhouwer, who had recommended that investors buy the stock when it was trading at $12, said the current price increases the risk of a decline. But he said the stock, which traded as high as $32.625 in the last year, is a good long-term investment.