Updated from 4:15 p.m. to include additional information on Alibaba.
SAN FRANCISCO ( TheStreet) – Twitter (TWTR) tanked after reports surfaced that its founder Evan Williams sold shares in the social media company for the first time. Meanwhile, Alibaba (BABA) stumbled as U.S. retailers ganged up on the Chinese e-commerce company and On Semiconductor (ONNN) soared after it announced a $1 billion share repurchase program.
Twitter fell 6.5% to close at $39.04 on Monday. The company took a beating after The Wall Street Journal reported late Friday that its founder had sold 719,000 shares that week, ranging in price between $39.83 to $40 a share. The total sale was approximately $28.7 million.
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That sale represented roughly 2% of Williams' Twitter stake. Williams still has plenty of stock, as he held a 9.5% stake in the San Francisco-based company as of March, according to the report.
Twitter went public a year ago, setting its IPO price at $26 a share.
Although investors grew skittish over the sale, one thing to keep in mind it was a pre-arranged trade that was set 90 days ago, according to The Journal. It's a common practice where executives of public companies sell shares under a pre-set plan, in order to reduce the perception that the shares are being sold based on inside knowledge.