Callon Petroleum Co. (NYSE: CPE) closed its public offering of 29.9 million common shares including 3.9 million shares sold to underwriters.

The underwriters exercised their option to purchase additional shares on Sept. 7, the company said Sept. 12.

Following this issuance, Callon now has about 161 million common shares issued and outstanding.

Total net proceeds after underwriters' discounts and commissions and estimated offering expenses will be about $422.1 million. Proceeds will likely fund the pending Plymouth Acquisition, and if it is not fulfilled they will support exploration and development activities and general corporate purposes.

Morgan Stanley, RBC Capital Markets, SunTrust Robinson Humphrey, Credit Suisse and J.P. Morgan are joint book-running managers for the offering.

Callon Petroleum Co. is based in Natchez, Miss.