Macerich (MAC) said late Monday it launched a public offering of 18 million common shares.

The company expects to grant a 30-day overallotment option to the underwriters to acquire up to 2.7 million additional shares.

Macerich said it plans to use the net proceeds of the offering, along with cash on hand, to repay the $478 million mortgage loan secured by its Washington Square property, among other things.

The company's shares were down 2.2% in after-hours activity.