Any sale or transfer of corporate stock must be approved by the Agency in writing and must be to an eligible individual or entity in accordance with §4279.108(a) and 4279.108(b) of this chapter. In the event a portion of the borrower's stock is sold or transferred, the Agency may require personal or corporate guarantees from those then owning a 20 percent or more interest in the borrower in accordance with §4279.132 of this chapter.