All loans shall be secured by such collateral as the Chief Executive Officer may require, including without limitation, a first priority lien on the BETR reimbursement, a mortgage or security interest in real estate, buildings or personal property of the business entity, subject only to such other encumbrances as the Chief Executive Officer may approve, assignment or pledges of leases, and personal or corporate guarantees. Personal guarantees of the principals shall be required unless a compelling reason justifies the waiver of this requirement.
94- 457 C.M.R. ch. 320, § 6