I. Magnin & Company was a San Francisco, California-based high fashion and specialty goods luxury department store.

In the 20th century I. Magnin imported clothing by major designers including Jeanne Lanvin, Hattie Carnegie, and Christian Dior.

When designer Christian Dior visited, he toured the Union Square store, and called it the "White Marble Palace".

[2] Daughter Flora married Myer Siegel, who launched a namesake department store in Los Angeles, which would later become a chain.

In Los Angeles in 1897 and 1898, I. Magnin & Co. advertised its wares for retail sale at 237 South Spring Street, noting that Mr. Myer Siegel was the manager.

In the late 1950s the combined chain expanded into the Southern California suburbs by opening the Fashion Square concept in Santa Ana in 1958, the San Fernando Valley (Sherman Oaks) in 1962 and Del Amo (Torrance) in 1965.

Even before the acquisition closed, it pulled the plug on the remainder of the I. Magnin chain, eventually selling four stores (Carmel, Beverly Hills, San Diego, and Phoenix) to Saks Fifth Avenue and ultimately converting six former I. Magnin locations in Palo Alto, Walnut Creek, Woodland Hills, Palm Desert, Newport Beach, and Palos Verdes to specialty Macy's or Bullock's locations, replicating the success of the 1991 conversion of I. Magnin at South Coast Plaza in Costa Mesa, California, into a separate Bullock's Men's location.