Earlier this month the Whitney Museum of American Art celebrated the opening of an exhibition by the painter Amy Sherald — Michelle Obama’s official portraitist — with a champagne toast over lush arrangements of daffodils and yellow ranunculus.

At the Museum of Modern Art, another recent blowout event honored an ambitious retrospective of the revered painter and sculptor Jack Whitten, who died in 2018.

Further uptown, the multimedia art star Rashid Johnson took over the Solomon R. Guggenheim Museum with a solo show of almost 90 works and live performances. And next month, the conceptual artist Lorna Simpson will debut a major show of paintings at the Metropolitan Museum of Art.

What these in-demand artists have in common is their deep-pocketed Swiss dealer, Hauser & Wirth. The gallery’s artists are so dominant in New York’s leading museums this season that some in the art world are calling it “Hauser spring.”

Hauser & Wirth’s prominence comes at a time when the most powerful dealers in the commercial art world play an increasingly large role in helping support the city’s ambitious museum shows. A New York Times analysis of solo exhibitions since 2019 shows that out of 350 exhibitions by contemporary artists, nearly 25 percent went to artists represented by just 11 of the biggest galleries in the world.

And within that tiny slice of the art market, the most exhibitions came from Hauser & Wirth artists, with 18 shows over the last six and a half years, outpacing even established names in the American art world like Larry Gagosian and David Zwirner.