For purposes of this subchapter, the critical capital level for each enterprise shall be the sum of -

(1)

1.25 percent of the aggregate on-balance sheet assets of the enterprise, as determined in accordance with generally accepted accounting principles;

(2)

0.25 percent of the unpaid principal balance of outstanding mortgage-backed securities and substantially equivalent instruments issued or guaranteed by the enterprise that are not included in paragraph (1); and

(3)

0.25 percent of other off-balance sheet obligations of the enterprise not included in paragraph (2) (excluding commitments in excess of 50 percent of the average dollar amount of the commitments outstanding each quarter over the preceding 4 quarters), except that the Director shall adjust such percentage to reflect differences in the credit risk of such obligations in relation to the instruments included in paragraph (2)