Updated from 9:48 a.m. EST
The announcement sent the share prices of the companies involved flying in different directions on heavy trading.
Inamed's stock jumped $6.84, or 9.2%, to close at $81.28 in response to the Allergan offer, which is worth $84 in cash, or 0.8498 shares of Allergan. More than 5.8 million Inamed shares changed hands, or nearly 10 times the average daily volume for the past three months.Shares of Medicis plunged $2.97, or 10%, to $26.70 as trading volume topped 12 million shares, or 11 times the daily average for the last three months. Medicis made a bid for Inamed in March, which was worth $75 a share, or $2.8 billion at the time. Medicis, which makes treatments for skin diseases and other products, offered $30 cash plus 1.4205 of its shares. Allergan, which specializes in skin-care products and eye-disease medications, saw its stock skid $2.50, or 2.5%, to $96.35 in active trading. In addition, shares of Mentor (MNT) rose 65 cents, or 1.2%, to $55.26. Like Inamed, Mentor is based in Santa Barbara, Calif., and both companies are developing silicone-gel breast implants.