PennyMac Mortgage Investment Trust (PMT) announced the offering of 15 million common shares of stock Friday morning. 

The offering is expected to close on Aug. 22, 2012, with underwriters retaining a 30-day option to acquire an additional 2.25 million shares.

Proceeds from the sale will be used to fund the acquisition of a portfolio of residential whole mortgage loans. In addition, funds will be allocated to the firm's correspondent lending business and will be used to help with aquisitions related to mortgage loans and investments.

PennyMac shares were selling for $21.80 at market close on Thursday, Aug. 16. The 15-million common share offering was announced a day later.

On Thursday, PennyMac said it would offer just 12 million shares, but the official offering rose to 15 million shares by Friday morning.