Alphamab Oncology's (HKG:9966) non-executive director, Cho Man, informed the firm on Feb. 27 his spouse disposed of 10,000 shares on the market at HK$6.15 apiece without first notifying the company, a Friday Hong Kong bourse filing said.

Shares of the cancer drug company were up nearly 4% in Monday afternoon trading.

The move is a breach of the Hong Kong bourse's listing rules, which state that directors cannot deal in a firm's securities on the day or 60 days before the publication of its annual results, or during any period of delay in the publication.

The disposal occurred during a period of delay in publication in what Cho said was an inadvertent oversight. Cho confirmed he did not possess any inside information of the firm when the sale took place.

As of Sept. 19, Cho, along with his spouse, holds 230,000, or 0.02%, shares in the company.