The entrepreneur and patron of the arts Reinhold Würth was the buyer of Max Beckmann's "Self-Portrait Yellow-Rose".
A spokeswoman for the company confirmed a corresponding report by the "Handelsblatt".
The 87-year-old entrepreneur told the newspaper that he bought the picture for 20 million euros.
"Sooner or later it will appear in our exhibitions, so everyone can look at it for free." When asked how many works of art Würth now has, the billionaire said: "We're moving towards 20,000."
The work was recently auctioned at the Grisebach auction house in Berlin for a record price.
Grisebach had said: "It is the highest price that has ever been achieved in Germany for a work of art at an auction, and the second highest price worldwide for a self-portrait of the artist."
The self-portrait of Beckmann (1884-1950) came from a Swiss private collection.
The artist painted the work during his exile in Amsterdam, where he had emigrated after the Nazis came to power in Germany.
In the painting itself, however, there are no direct references to the world situation at the time.
Beckmann gave it to his wife Mathilde "Quappi" Kaulbach, who kept it until her death in 1986.
According to the information, the “Self-portrait yellow-pink” was one of the rare self-portraits that was still in private hands.