ASML has taken close to 100,000 square feet at 50 Danbury Road in Wilton Corporate Park, about half the available space in the building that was the subject of a lender’s foreclosure action this year.

Semiconductor companies use ASML’s machines to concentrate patterns of light on the chips they make to create circuit lines. ASML has spent the past few years investing in a major upgrade to its Wilton factory, subleasing overflow offices across the street at the former headquarters of Sun Products at 60 Danbury Road to accommodate employees during those renovations.

ASML is now moving about 400 employees at that location next door to 50 Danbury Road and into newly renovated offices at its main plant across the street at 77 Danbury Road, the company confirmed Tuesday.

The Wilton Corporate Park campus lists as its owner a limited liability company controlled by Davis Marcus Partners that created as a joint venture between The Davis Cos. and Marcus Partners, with the firms operated separately from offices in Norwalk and Boston.

Late last month, a Connecticut judge issued an order approving a foreclosure action on a loan covering the 50 Danbury Road building ASML has leased, with the LLC having owed some $65 million on the building and another $7 million outstanding on a loan for 64 Wilton Road next door where ASML has had an office presence.

“This lease .... is great news for the market and the asset,” said David Fiore, New York regional director of Marcus Partners, in an email response to a Hearst Connecticut Media query on the ASML lease. “Although we will no longer be the property owner, Davis Marcus Partners is staying involved to oversee leasing, property management and some upcoming renovations.”

ASML will join financial services giant AIG in the office building, which recently committed to retaining nearly 50,000 square feet of space at 50 Danbury Road, a reduction of more than 40 percent of the space it had previously as reported by Trepp, which monitors loans backed by commercial real estate nationally.

The marketing services firm Epsilon recently moved its own offices from 50 Danbury Road a short distance north to the Wilton Woods corporate park at 10 Westport Road, with Trepp indicating the health-care industry analysis firm Cotiviti is also vacating its space at the building a year after the company was acquired by Verscend Technologies, which dropped its corporate name in favor of Cotiviti.

Alex.Soule@scni.com; 203-842-2545; @casoulman