LIQUIDITY AND CAPITAL RESOURCES
Our primary sources of funds are borrowings under master repurchase agreements, equity offerings, asset sales and monthly principal and interest payments on our investment portfolio. Because the level of our borrowings can be adjusted on a daily basis, the level of cash and cash equivalents carried on our balance sheet is significantly less important than the potential liquidity available under our borrowing arrangements. We currently believe that we have sufficient liquidity and capital resources available for the acquisition of additional investments, repayments on borrowings, maintenance of any margin requirements and the payment of cash dividends as required for our continued qualification as a REIT. To qualify as a REIT, we must distribute annually at least 90% of our taxable income. To the extent that we annually distribute all of our taxable income in a timely manner, we will generally not be subject to federal and state income taxes. We currently expect to distribute all of our taxable income in a timely manner so that we are not subject to federal and state income taxes. This distribution requirement limits our ability to retain earnings and thereby replenish or increase capital from operations.
As part of our investment strategy, we borrow against our investment portfolio pursuant to master repurchase agreements. We expect that our borrowings under such master repurchase agreements will generally have maturities ranging up to one year, but may have maturities up to five years or longer. Our leverage may vary periodically depending on market conditions and our Manager's assessment of risks and returns. We generally would expect our leverage to be within six to eleven times the amount of our stockholders' equity. However, under certain market conditions, we may operate at leverage levels outside of this range for extended periods of time.
As of March 31, 2015, we had $54.3 billion of repurchase agreements outstanding used to fund acquisitions of agency securities and we had an additional $3.8 billion of repurchase agreements outstanding used to fund temporary holdings of U.S. Treasury securities, which we exclude from our leverage measurements due to the highly liquid and temporary nature of these investments. Inclusive of our net TBA position, our "at risk" leverage ratio was 6.4x as of March 31, 2015, compared to 6.9x as of December 31, 2014, measured as the sum of our agency repurchase agreements, net TBA position (at cost), net receivable / payable for unsettled agency securities and debt of consolidated VIEs divided by the sum of our total stockholders' equity less the fair value of our investment in REIT equity securities as of period end. Excluding our net TBA position, our leverage ratio was 5.8x our stockholders' equity as of March 31, 2015, compared to 5.3x as of December 31, 2014.
As of March 31, 2015, our agency repurchase agreements had a weighted average cost of funds of 0.41% and a weighted average remaining days-to-maturity of 164 days, excluding amounts borrowed under U.S. Treasury repurchase agreements, compared 0.41% and 143 days, respectively, as of December 31, 2014.
To limit our exposure to counterparty credit risk, we diversify our funding across multiple counterparties and by counterparty region. As of March 31, 2015, we had master repurchase agreements with 34 financial institutions located throughout North America, Europe and Asia. As of March 31, 2015, less than 4% of our stockholders' equity was at risk with any one repo counterparty, with the top five repo counterparties representing approximately 15% of our stockholders' equity. The table below includes a summary of our repurchase agreement funding by number of repo counterparties and counterparty region as of March 31, 2015. For further details regarding our borrowings under repurchase agreements and other debt as of March 31, 2015, please refer to Note 5 to our consolidated financial statements in this Quarterly Report on Form 10-Q.
March 31, 2015
Number of Counter-Parties
Percent of Repurchase Agreement Funding
Amounts available to be borrowed under our repurchase agreements are dependent upon lender collateral requirements and the lender's determination of the fair value of the securities pledged as collateral, which fluctuates with changes in interest rates, credit quality and liquidity conditions within the investment banking, mortgage finance and real estate industries. In addition, our counterparties apply a "haircut" to our pledged collateral, which means our collateral is valued at slightly less than market value.