Investment Company Development Act - Amends the Small Business Investment Act of 1958 to set the interest rate on loans guaranteed by the Small Business Administration (SBA) to small business investment companies at three percent per annum.

Authorizes the Small Business Administration to guarantee up to 75 percent of the funds advanced by small business investment companies to start small business concerns. Limits such guarantees to not more than 25 percent of the private paid-in capital of the small business investment company.

Makes the Associate Administrator for investment of the SBA responsible for the administration of the small business investment program and removes any other duties.

Permits small business investment companies to recognize, for accounting purposes, specified non-cash gains and the proceeds from the issuance of capital notes when such notes have a maturity of at least ten years.