Discovery’s lightly traded class B shares surged 80% on Wednesday, showing a spike in volume and divergence from the company’s class A shares that is highly unusual.

The class B stock, which often sees volume of less than 10,000 shares in a day, had already changed hands about 600,000 times as of noon ET, according to FactSet. Meanwhile, the class A shares had risen about 3% on a much more modest jump in volume, and its non-voting class C shares were flat.

Shares of Discovery have fallen sharply over the past week as Archegos Capital Management was forced to liquidate its position in the communications company and several other names. Those sell-offs hit both share classes of Discovery in a similar manner, however, unlike the moves on Wednesday.

Discovery declined to comment.

The class B shares account for 10 votes per share versus one vote per share for class A, according to Discovery’s investor relations website. Roughly 95% of the class B shares are held by media executive John Malone, according to FactSet.

–CNBC’s Chris Hayes contributed to this report.