Shares in Shenzhen-based online sports lottery operator 500.com went on a roller coaster ride this week on rumors of corruption investigations and the promise of a restart to China’s online lottery sales.

On Monday, 500.com shares fell nearly 10% after White Diamond Research analyst Adam Gefvert tweeted that “smart money with the inside track” was shorting 500.com stock. Gefvert added that there was “major corruption going on there, the Chinese Gov is cracking down on it.” 500.com spokesman Daniel Yan subsequently told Forbes contributor Yue Wang that Gefvert was a short-seller spreading groundless rumors.

It’s not the first time that analyst speculation has waylaid 500.com. Last May, 500.com shares tanked after analysts misinterpreted a communiqué from China’s lottery administrators that appeared to call in question 500.com’s right to operate in the country. For the record, no company has been officially licensed to offer online lottery sales in China, but 500.com and China SMG were approved to take part in an online pilot program.

Rumors can give as well as take. On Thursday, 500.com shares closed up nearly 18% to $12.29 on reports that China is preparing to restart online lottery sales following their suspension on March 1. The temporary shutdown, which was reportedly sparked by the discovery that some online operators weren’t reporting all their sales to provincial lottery administration centers, affected around 10% of 500.com’s overall revenue stream.