The Unaxis group - formerly Oerlikon-Bührle - is taking a majority stake in the ESEC semiconductor assembly equipment manufacturer of Cham.
Unaxis already had about 27 per cent of ESEC shares and is now exercising the option agreed last November to buy the 525,000 registered shares from ESEC's founder, Karl Nicklaus, for SFr246 million.
In a statement, Unaxis said it viewed its engagement in ESEC as a long-term investment.
"By taking this step, Unaxis is resolutely pursuing its strategic expansion in the area of high technology, with particular emphasis on information technology," it said.
"ESEC is to remain a publicly-listed company as a means of maintaining its entrepreneurial dynamism and upholding the best interests of its shareholders," it added.
The company is to be given a modern capital structure, with a split of the bearer shares into more easily tradable unified shares.
ESEC's founder and chairman, Nicklaus, has expressed his satisfaction with the plans.
"For me, the established goals have been achieved. I'm pleased to be able to pass on a healthy and successful company within the framework of this order of succession," he commented.
swissinfo with agencies