ChannelAdvisor, which helps merchants sell via eBay, Amazon.com and other websites, reported that client same-store sales on eBay jumped 28.2 percent in July from 12 months ago.

That was the fastest year-over-year growth since September 2009, when ChannelAdvisor began tracking client sales on eBay.

Fixed-price sales on eBay surged a record 33.1 percent in July, compared with a year earlier, while auction-based sales dipped 1.1 percent, ChannelAdvisor added.

"We're seeing name-brand, larger retailers do very well on eBay and eBay's daily deal program continues to drive significant revenue for top-tier sellers," ChannelAdvisor Chief Executive Scot Wingo wrote in a blog on the firm's website.

EBay, once a scrappy auction site for mom and pop sellers, is enticing some of the world's largest retailers by arguing it can help them improve competition against e-commerce leader Amazon.com Inc.

EBay shares rose as high as $45.54, before closing up 3 percent at $45.32 on Nasdaq. In late July, eBay shares hit a multi-year high of $46.15.

(Reporting By Alistair Barr; editing by Andre Grenon and Richard Chang)

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