U.S. online apparel spending grew over 32 percent in the third quarter compared to a year ago. Specialty retailers accounted for the largest share of sales, according to new research.

Sites operated by specialty retailers - such as VictoriasSecret.com and OldNavy.com -accounted for the largest share of sales with 46 percent of total dollars spent. Department store sites held a 21 percent share, while online only retailers, such as Amazon.com, accounted for 16 percent.

The firm indicated that an influx of new buyers primarily drove the increase, with five out of six apparel site segments showing double-digit percentage increases in buyers. Department store sites led the way with 60 percent growth in number of buyers, followed by manufacturer and specialty store sites, which each saw 48 percent growth.

Analysis also revealed that specialty store sites, in particular, have fared well during the past year, increasing their market share by more than 3 points, while department store sites rose 1 point. Catalog sites lost approximately 2 share points, while discount store sites lost 1 share point.

Retail