NEW YORK - A COLLECTION of more than 3,000 inverted stamps has sold at auction in New York for more than US$5 million (S$7.3 million).

The two-day auction by Spink Shreves Galleries ended Friday. The collection was amassed by Pittsburgh stockbroker Robert H. Cunliffe, who died last year.

Charles Shreve, president of the Dallas-based gallery, says it was the most comprehensive collection of inverts ever formed.

Inverted stamps result when different colours and elements are printed in separate press runs and a sheet gets flipped upside-down between press runs.

Mr Cunliffe's collection included an 'inverted Jenny,' a famous US stamp from 1918 featuring an upside-down biplane. -- AP