Shares of Centessa Pharmaceuticals plc (NASDAQ:CNTA) plummeted by 5.76% on Tuesday after the company announced a proposed public offering of $150 million worth of American Depositary Shares (ADSs), each representing one ordinary share.

The biopharmaceutical company stated that it intends to grant the underwriters a 30-day option to purchase up to an additional $22.5 million of ADSs offered in the public offering. Following the announcement, CNTA's stock price dropped by 4.2% in after-hours trading.

Public offerings are often seen as a dilutive event for existing shareholders, as they increase the total number of outstanding shares, leading to a decrease in the stock's value. Investors may have reacted negatively to the proposed offering, resulting in the significant plunge in CNTA's share price.