Tiffany & Young changed its name to Tiffany & Company in 1853.
The business began in New York City in 1837 as a stationery and fancy-goods emporium founded by Charles Lewis Tiffany and John B. Young. Its earliest recorded name was Tiffany, Young and Ellis, reflecting the original partners. The store operated at 259 Broadway in Lower Manhattan and sold a broad range of goods rather than specializing exclusively in jewelry.
The 1853 name change coincided with Charles Tiffany taking control of the firm and steering it toward jewelry. The shorter identity, Tiffany & Company, eventually became widely known as Tiffany & Co. The company was formally incorporated in 1868, so incorporation is a separate milestone and not the answer to this question.
Another common mix-up is 1837, which marks the company’s founding, not its renaming. The company also published its first Blue Book mail-order catalog in 1845. Tiffany’s early fixed-price, cash-only retail policy helped distinguish it from many nineteenth-century shops, where bargaining and credit were more common.