We are an alternative asset management firm offering yield solutions to retail and institutional investors. We focus on credit-related investment strategies, primarily originating senior secured loans to private middle market companies in the United States that have revenues between $50 million and $1 billion. We generally hold these loans to maturity. Our national direct origination franchise provides capital to the middle market in the U.S. For over 17 years, we have provided capital to over 400 companies across 35 industries in North America.
We manage three permanent capital vehicles, two of which are Business Development Companies "BDCs", and a credit interval fund, as well as long-dated private funds and Separately Managed Accounts ("SMAs"), with a primary focus on senior secured credit. As of December 31, 2018, we had $4.7 billion of AUM in two business development companies, MCC and SIC, as well as private investment vehicles. Our compounded annual AUM growth rate from December 31, 2010 through December 31, 2018 was 21%, and our compounded annual Fee Earning AUM growth rate was 15%, which have both been driven in large part by the growth in our permanent capital vehicles. Typically the investment periods of our institutional commitments range from 18 to 24 months and we expect our Fee Earning AUM to increase as capital commitments included in AUM are invested.
In general, our institutional investors do not have the right to withdraw capital commitments and to date; we have not experienced any withdrawals of capital commitments. For a description of the risk factor associated with capital commitments, see "Risk Factors - Third-party investors in our private funds may not satisfy their contractual obligation to fund capital calls when requested, which could adversely affect a fund's operations and performance."