Each such foreign banking corporation shall hold, in this State, currency, bonds, notes, debentures, drafts, bills of exchange or other evidences of indebtedness or other obligations payable in the United States or in United States funds or, with the prior approval of the Commissioner, in funds freely convertible into United States funds, or such other assets as the Commissioner shall permit, in an amount which shall bear such relationship as the Commissioner shall prescribe to liabilities (including contingent liabilities) of such foreign banking corporation payable at or through its banking office in this State, including acceptances, but excluding amounts due and other liabilities to other offices, agencies or banking offices of, and wholly-owned (except for a nominal number of directors’ shares) subsidiaries of, such foreign banking corporation and such other liabilities (including contingent liabilities) as the Commissioner shall permit. For the purposes of this Section the Commissioner (a) shall value marketable securities at principal amount or market value, whichever is lower, (b) shall have the right to determine the value of any nonmarketable bond, note, debenture, draft, bill of exchange, other evidence of indebtedness, or of any other obligation held by or owed to the foreign banking corporation or its banking office within this State, and (c) in determining the amount of assets for the purpose of computing the above ratio of assets to liabilities, may exclude any particular asset but shall give credit to assets required to be maintained pursuant to Section 11 and, subject to such rules and regulations as the Commissioner may from time to time promulgate, to deposits and credit balances with unaffiliated banking institutions outside this State if such deposits or credit balances are payable in United States funds or in currencies freely convertible into United States funds. Credit given for such deposits and credit balances may not, however, exceed in aggregate amount such percentage, but not less than 8%, as the Commissioner may from time to time prescribe of the aggregate amount of liabilities of such foreign banking corporation, determined as provided in this Section. If, by reason of the existence or the potential occurrence of unusual and extraordinary circumstances, the Commissioner deems it necessary or desirable for the maintenance of a sound financial condition, the protection of depositors, creditors, and the public interest, and to maintain public confidence in the business of the banking office of a foreign banking corporation, he may, notwithstanding anything to the contrary contained in this Section, reduce the credit to be given for deposits and credit balances with unaffiliated banking institutions outside this State and require such foreign banking corporation to deposit, in accordance with such rules and regulations as he has promulgated, the assets required to be held in this State pursuant to this Section 13 with such State banks or national banks as such foreign banking corporation may designate and the Commissioner may approve.