PennyMac Mortgage Investment Trust said late Thursday that it plans to offer 12 million common shares in a public offering.

The Moorpark mortgage real estate investment trust intends to use net proceeds to help pay for a portfolio of residential whole mortgage loans and for general corporate purposes. Underwriters BofA Merrill Lynch, Citigroup and Credit Suisse Securities will have a 30-day option to purchase up to an additional 1.8 million shares.

The offering would have grossed more than $261 million at Thursday’s closing price of $21.80 on the New York Stock Exchange. Shares fell more than 3 percent in after-hours trading.