S Corporation ESOP Promotion and Expansion Act of 2010 - Amends the Internal Revenue Code to: (1) extend to all domestic corporations, including S corporations, provisions allowing deferral of tax on gain from the sale of employer securities to an S corporation-sponsored employer stock ownership plan (ESOP); (2) allow a tax deduction for interest incurred on loans to S corporation-sponsored ESOPs for the purchase of employer securities; and (3) transfer liability for payment of estate tax on transfers of employer securities to an S corporation-sponsored ESOP from the estate executor to the ESOP.
Directs the Secretary of the Treasury to establish the S Corporation Employee Ownership Assistance Office to foster increased employee ownership of S corporations.