LONDON — In recent years, the competition between the world’s two largest auction houses, Sotheby’s and Christie’s, has seemed at times like a bit of an unfair fight.

Sotheby’s, which is publicly traded, has lost out to its privately held archrival for several headline-grabbing consignments. Last year, Christie’s sold the collection of Peggy and David Rockefeller for $835 million, the highest-grossing auction ever of a private collection. In 2017, Christie’s sold Leonardo da Vinci’s “Salvator Mundi” for $450.3 million, the highest auction price ever for a work of art.

Both auctions were underpinned by financial guarantees arranged by Christie’s, which since 1998 has belonged to a holding company owned by the French billionaire François-Henri Pinault.

Wendy Goldsmith, a London-based art adviser and former head of 19th-century European art at Christie’s, noted the advantage gained by an auction house owned by a wealthy individual. “If you wanted to get something done,” she said, “you went to the man with deep pockets.”