Deutsche Bank currently owns around 56,000 works of art - the most significant collection of post-war drawings and photographs in the world.

The Hypovereinsbank, a member of Unicredit, possesses around 20,000 works with a focus on international contemporary art.

The chemical and pharmaceutical giant Bayer holds a 5,500-piece collection of 20th-century paintings, drawings, prints, and sculptures.

A good 240 artworks from the Bayer collection, never before on public display, are currently being shown in Berlin to celebrate the firm's 150th anniversary. Works include Picasso's lithograph "Figure 21.11.1948," Max Beckmann's "Still Life with Orchids and Green Bowl" and Gerhard Richter's "Abstract Image (555)."

Bayer began acquiring artworks in 1912, making it the oldest corporate collection in Germany. But why do so many businesses opt to invest in art?

All part of the image

"Whereas in the past the patriarch would buy artworks out of personal interest to hang in the office, many companies today use art as part of marketing strategies to improve their image," Wolfgang Ullrich, a professor of art history at the Karlsruhe University of Arts and Design, told DW.

That's especially true of businesses which don't produce glitzy, photogenic products, like banks or insurance companies.

"It's useful for a company boss to present a piece of contemporary art, whereas the head of company that makes cars can always present the latest model," pointed out Ullrich. Artworks are often prominently displayed in foyers and conference rooms as a means to convey a carefully thought-out image.

The motivation for corporate forays into art is often based on the argument of social responsibility. However, the interest in art is sometimes genuine, Ullrich said.

Corporate patronage also provides much needed financial support: "There are numerous grants for young artists, and also commissions, without which many artists wouldn't be able to continue in the profession."

Alessa Rather from the Association of Arts and Culture of the German Economy points to the art institutions financed by a growing number of businesses in order to "introduce" their employees to art.

"Employees can talk to curators, appreciate art together and organize the loan of a painting for their office or conference room," Rather explained.

The 'politics of distinction'

Picasso's or Beckmann's, though, are usually only reserved for the director's office. That's often mainly due to the sheer scale of the works - and, of course, the issue of insurance, Rather said.

But there's no doubt that it's also a matter of the "politics of distinction," as Ullrich phrased it, meaning some companies use art to create or enforce the hierarchical structures of the business.

Corporate art collections in Germany are remarkable for their diversity and sheer number - 300 according to Rather. In the sphere of corporate collecting, Germany is an international leader.

That's down to the country's strong and especially culturally engaged middle-class, the director of the Association of Arts and Culture of the Germany Economy, Stephan Frucht, explained. People like the businessman Reinhold Würth, who made billions manufacturing screws and "built multiple museums in order to make his art collection accessible to the public."

Then there's the Ritter family behind Ritter Sport, the brand famous for its square-shaped chocolate bars. The company has its own museum specializing in the use of the square in 20th and 21st century art.

The treasures possessed by some corporations only really to come light in times of financial crisis, namely, when a firm is forced to sell works of art in order to generate capital.

Commerzbank is a prime example. In 2010, the sculpture "L'Homme qui marche I" by Swiss artist Alberto Giacometti was sold at auction for 75 million euros ($96.3 million) - then the most expensive artwork in the world.

Wolfgang Ullrich believes, however, that art is rarely bought as a financial investment. Investment "surely played a part in the incredible boom in the art market over the past few years, but it's not generally the case," he said.

Abstract, contemporary and disengaged

Ullrich doesn't believe that the purchase and sale of artworks by corporations has such a significant impact on the art market. "If half of all businesses suddenly closed and sold their art collections then it would surely have an influence. Or if a large number of artworks by the same artist were auctioned at the same time."

Like those of Gerhard Richter. The German painter, sculptor and photographer is a favorite among corporate collectors. "There are scarcely any big corporations in Germany, that collect art, that don't own works by Gerhard Richter," Ullrich said.

In terms of the type of art corporations - many of which employ an in-house curator - collect, abstract and contemporary art are by far the most popular.

"There's a certain disengagement, but also something spirited," Ullrich explained. "You're unlikely to find anything scandalous in a corporate collection. But then there are also very few landscape paintings, which are harmless."