According to new data from Slice Intelligence, Nordstrom's dressy-casual Halogen line generated 11 times the digital revenue of Amazon's best-selling private brand, Lark & Ro, from January 2016 through February 2017.
Macy's Alfani label rang up online sales that were nearly 10 times greater over that same time frame, Slice said.
Sales of Amazon's private fashion designs grew an impressive 26 percent in the fourth quarter compared with the prior year. That was roughly in line with the rate of expansion among Nordstrom's brands. Macy's private label brands grew 18 percent over a comparable period.
Slice pulled its data by scanning the online shopping receipts of more than 68,000 U.S. consumers.
"Amazon's new private label brands will need time to develop that familiarity," Ken Cassar, principal analyst at Slice Intelligence, said in a statement. "Still, competitive apparel brands...should keep a close eye on Amazon."