The sale comes after Yang sold 550,000 shares in May, with proceeds totaling $8.1 million, according to filings.
Earlier this month, Yang transferred 3 million shares of his stock to a "blind trust," in compliance with SEC rules allowing company insiders to create prearranged plans to sell their stock. The blind trust, established before the close of Yahoo's most recent insider trading "window," will have complete control over the sale of Yang's 3 million shares over a 12-month period.
The recent round of sales is a drop in the bucket for Yang, who co-founded Yahoo in 1995 with his Stanford University friend David Filo. According to the company's most recent proxy filing, Yang holds a 7.5 percent stake in the company, amounting to nearly 45 million shares.
A Yahoo representative did not return requests for comment.
Yahoo shares, which traded at $15.45 on Friday, remain well below their all-time high but have rebounded from a 52-week low of $8.02.