Sotheby’s will auction two paintings by Joan Mitchell from the collection of Rockefeller University during its 20th century evening sale on November 19.

City Landscape (1955) has an estimate of $15 million to $20 million, and is the larger of the two. The other is an untitled painting, also from 1955, that carries an estimate of $9 million to $12 million. Both works date to the era when Mitchell was ascending as one of the foremost artists of the Abstract Expressionist movement.

Rockefeller University isn’t in a tight spot financially, with an endowment worth $2.5 billion and a five-year-fundraising campaign that ended earlier this year after bringing in $777 million. But after nearly seven decades of ownership, the university is selling the two paintings in light of the rising value of works by the artist, and to fund future biomedical research.

“It had reached that point where what [the university] can do with these proceeds will benefit mankind more than than hanging the pictures on their walls,” Christie’s vice chairman Max Carter told ARTnews.

The works have also been rarely seen by anyone one than campus staff, visitors, and leading scientists, among them 26 Nobel laureates in medicine and chemistry. “Untitled was never, as far as we know, exhibited, and City Landscape was exhibited twice, once in 1955 and once in 1957,” Carter said. “Then both were bought in 58 and they were never really again, taken off of the campus.”

For many years, City Landscape hung in the Abby Aldrich Rockefeller Dining Room next to a work by Franz Kline, while the untitled painting hung for many years in the university president’s residence.

This isn’t the first time Rockefeller University has sold an artwork. In 1977, the institution sold Jacques-Louis David’s 1788 painting Antoine-Laurent Lavoisier and his Wife to help deal with deficits. Oil industrialist Charles Wrightsman purchased the work and donated it to the Metropolitan Museum of Art. Proceeds from the sale, about $4 million, were used to endow two professorships and four graduate fellowships.

Last November, Mitchell’s auction record was reset at Christie’s when an untitled painting from around 1959 sold for $29.2 million with fees. The Abstract Expressionist’s previous record was set in 2018 by Blueberry (1969), which sold for $16.6 million also at Christie’s in New York.

In May, Sotheby’s auctioned four guaranteed Joan Mitchell paintings from four different decades, with three of them selling above estimate. The priciest one, her abstraction Noon (ca. 1969), sold for $22.6 million. And on the first day of this year’s Art Basel in June, ARTnews reported that David Zwirner gallery sold a Joan Mitchell diptych titled Sunflowers (1990–91) for $18 million.

Carter said “truly important paintings” by Mitchell from the 1950s are “fewer and further between” compared to work made in later decades. “We felt that these estimates reflected that these were among the best that we’ve seen from this period, as well as the fact that their history, their provenance, their purpose, really set them apart from anything else that we’ve seen,” he told ARTnews.

Correction, October 31, 2024: A previous version of this article stated Rockefeller University’s endowment is $2.5 million. It is $2.5 billion. ARTnews regrets the error.