The expansive corporate art collection of the German fashion retailer SØR Rusche, which numbers over 4,000 works, will go under the hammer in what is estimated to be the largest auction of contemporary art in Germany—at least in terms of sheer volume, if not value—to date.

The menswear line decided to cash in on its collection in order to “finance the digital transformation of the company and secure the jobs of its employees in the long term,” its CEO Thomas Rusche told the Art Newspaper. His family—who were textile merchants as well as art collectors—amassed the collection over four generations. It includes more than 4,000 works of contemporary art and another 220 Old Master works by 17th-century Dutch and Flemish artists.

The collection will be sold in a series of sales at two auction houses over the course of 2019. The Old Masters, estimated to be worth a combined £1.9 million ($2.5 million), will go under the hammer at Sotheby’s London in the first week of May. The Cologne-based auction house Van Ham will undertake the larger, contemporary portion of the sale and is currently appraising the works to determine an overall estimate. On May 29, the first batch of 150 lots will go on sale in Germany and are expected to generate a combined €1 million ($1.1 million).

The quality and rarity of some of the works on offer means that they could likely exceed their individual estimates. Sotheby’s recently sold one highlight from SØR Rusche in its New York Old Masters evening sale in January; the unique still life by the 17th-century female Flemish artist Michaelina Wautier went for more than double its high estimate, selling for $471,000.

Neo Rauch, Alicja Kwade, and Daniel Richter are some of the major contemporary German artists included in the collection, which began in 2005 and has a particular focus on artists from Leipzig. Other artists represented include Tracey Emin, Phyllida Barlow, and Jonathan Meese.