At June 30, 2013, our portfolio consisted of 41 portfolio companies and was invested 43% in senior secured loans, 21% in senior secured notes, 21% in equity investments, 11% in unsecured or subordinated debt securities, and 4% in cash and cash equivalents. As compared to March 31, 2013, our equity and cash equivalents components increased 9% while our senior secured loans and unsecured or subordinated debt securities declined 9%. The composition of our portfolio invested in equity securities grew 5%, up from 16% last quarter end, resulting primarily from appreciation in our existing investments, as well as from additional equity securities received in connection with restructurings during the quarter. Our average portfolio company investment at amortized cost, excluding investments below $5.0 million, was approximately $22.6 million at June 30, 2013, down from $26.9 million at year end.
The weighted average yield of the debt and income producing equity securities in our portfolio at its current cost basis was 12.1% at June 30, 2013. The weighted average yields on our senior secured loans, and our other debt securities at their current cost basis were 11.5% and 13.2%, respectively, at June 30, 2013. Yields exclude common equity investments, preferred equity investments with no stated dividend rate, short-term investments and cash and cash equivalents. In certain of our portfolio companies, we hold equity positions ranging from minority interests to majority stakes, which we expect will contribute to our investment returns over time.
At June 30, 2013, we had $43.9 million in cash and cash equivalents, $334.0 million available under our senior secured, revolving credit facility, and $36.3 million payable for investments purchased. Our leverage stood at 0.45 times at quarter end, a reduction from .50 times at year end, providing us with available debt capacity under our asset coverage requirements of $371.8 million at June 30, 2013.