(Adds analyst comment and updates shares)
SAN FRANCISCO, July 11 (Reuters) - Amazon.com Inc shares hit another record on Thursday after e-commerce firm ChannelAdvisor Corp released strong online sales data.
ChannelAdvisor reported that client sales on Amazon.com jumped 30.6 percent in June, compared with the same month last year. That year-over-year growth rate was up from May's rate of 25.8 percent.
"The 30.6 percent reading for June was above our expectations," said Shawn Milne, an analyst at Janney Capital Markets, who was expecting growth of 20 percent to 25 percent.
ChannelAdvisor also reported that client sales on eBay's online marketplace rose 17.7 percent in June, compared with a year earlier. May's growth was 16 percent year-over-year.
ChannelAdvisor provides solutions to help merchants sell more on websites such as Amazon.com, eBay.com and Google Inc's shopping site. Investors watch the firm's data closely because it provides an early window into the performance of the leading U.S. e-commerce companies.
The second quarter is typically one of the slowest periods for online shopping, falling after the winter holiday buying binge and before the back-to-school rush. However, the ChannelAdvisor data suggests that Amazon and eBay performed solidly at the end of the second quarter.
"Together, these data points show that in June, all e-commerce channels performed better than in May," ChannelAdvisor Chief Executive Scot Wingo wrote in a blog on Thursday. In May, "overall retail sales were muted due to weather trends, which seem to have dissipated in June."
Amazon shares rose 2.1 percent to $298.39 in afternoon trading Thursday, having earlier touched a record $298.40. On Wednesday they reached a high of $293.34.
EBay shares rose 1.7 percent to $55.81 in afternoon action on Thursday.
EBay is an investor in ChannelAdvisor. (Reporting by Alistair Barr; Editing by Gerald E. McCormick, Chris Reese and Gunna Dickson)