A Macy’s unit will sell three malls to a developer.

Macy Acquiring Corp. said it has agreed in principle to sell the properties, including the Bay Fair Mall in San Francisco, to Westfield Holdings of Sydney, Australia, for about $363.5 million. The other shopping centers are the Garden State Plaza in Paramus, N.J., and the South Shore Mall in Bay Shore, N.Y. Also included in the deal, which is expected to close within 30 days, is a 44-acre development tract in Paramus. Westfield also owns the Westside Pavilion in West Los Angeles.