(a) The Office may take any of the actions set forth in paragraph (b) of this section when a self-insurer—

(1) Defaults on any of its LHWCA obligations;

(2) Fails to renew any deposited letter of credit or substitute a new letter of credit, indemnity bond or acceptable negotiable securities in its place;

(3) Fails to renew any deposited negotiable securities at maturity or substitute a letter of credit, indemnity bond or acceptable negotiable securities in their place; or

(4) Fails to comply with any of the terms of the Agreement and Undertaking.

(b) When any of the conditions set forth in paragraph (a) of this section occur, the Office may, within its discretion and as appropriate to the security instrument—

(1) Bring suit under any indemnity bond;

(2) Draw upon any letters of credit;

(3) Seize any negotiable securities, collect the interest and principal as they may become due, and sell or otherwise liquidate the negotiable securities or any part thereof.

(c) When the Office, within its discretion, determines that it no longer needs to collect the interest and principal of any negotiable securities seized pursuant to paragraphs (a) and (b) of this section, or to retain the proceeds of their sale, it must return any of the employer's negotiable securities still in its possession and any remaining proceeds of their sale.