An insurer may deposit and maintain on deposit with the Commissioner of Finance through the Commissioner of Insurance funds and eligible securities in amount exceeding its required deposit under this title by not more than $100,000, for the purpose of absorbing fluctuations in the value of securities held in its required deposit, and to facilitate the exchange and substitution of such required securities. During the solvency of the insurer any such excess deposit or any part thereof shall be released to it upon its request, transmitted through the Commissioner of Insurance. During the insolvency of the insurer such excess deposit shall be released only as provided in section 709 of this title.