standard master repurchase agreement. Typical supplemental terms and conditions include changes to the margin maintenance requirements, purchase price maintenance requirements, requirements that all controversies related to the repurchase agreement be litigated in a particular jurisdiction and cross default provisions. These provisions may differ for each lender and certain of these terms may not be determined until we engage in a specific repurchase transaction.
We may also obtain other sources of financing depending on market conditions. We may finance the acquisition of Agency RMBS by entering into TBA dollar roll transactions in which we would sell a TBA contract for current month settlement and simultaneously purchase a similar TBA contract for a forward settlement date. Prior to the forward settlement date, we may choose to roll the position out to a later date by entering into an offsetting TBA position, net settling the paired off positions for cash, and simultaneously entering into a similar TBA contract for a later settlement date. In such transactions, the TBA contract purchased for a forward settlement date is priced at a discount to the TBA contract sold for settlement/pair off in the current month. This difference (or discount) is referred to as the "price drop." The price drop is the economic equivalent of net interest carry income on the underlying Agency RMBS over the roll period (interest income less implied financing cost) and is commonly referred to as "dollar roll income." Consequently, dollar roll transactions represent a form of off-balance sheet financing. In evaluating our overall leverage at risk, we consider both our on-balance sheet and off-balance sheet financing.
During 2015, we formed a wholly-owned captive broker-dealer subsidiary, Bethesda Securities, LLC ("BES"). BES became operational and received final membership approval to the Fixed Income Clearing Corporation ("FICC") during the third quarter of 2016. BES has direct access to bilateral and triparty funding as a Financial Industry Regulatory Authority ("FINRA") member broker-dealer. As an eligible institution, BES also raises funds through the General Collateral Finance Repo service offered by the FICC, with the FICC acting as the central counterparty, and thus provides us greater depth and diversity of repurchase agreement funding while also lowering our funding cost and limiting our counterparty exposure.
Risk Management Strategy
We use a variety of strategies to reduce our exposure to market risks, including interest rate, prepayment, extension and credit risks. Our investment strategies take into account our assessment of these risks, the cost of the hedging transactions and our intention to qualify as a REIT. Our hedging strategies are generally not designed to protect our net asset value from "spread risk" (also referred to as "basis risk"), which is the risk that the yield differential between our investments and our hedges fluctuates. In addition, while we use interest rate swaps and other supplemental hedges to attempt to protect our net asset value against moves in interest rates, we may not hedge certain interest rate, prepayment or extension risks if we believe that bearing such risks enhances our return profile, or if the hedging transaction would negatively impact our REIT status.
Interest Rate Risk. We hedge a portion of our exposure to interest rate mismatches between the interest we earn on our longer term investments and the interest we pay on our shorter term borrowings. Because a majority of our funding is in the form of repurchase agreements, our financing costs fluctuate based on short-term interest rate indices, such as LIBOR. Because our investments are assets that primarily have fixed rates of interest and could mature in up to 40 years, the interest we earn on those assets generally does not move in tandem with the interest that we pay on our repurchase agreements; therefore, we may experience reduced income or losses due to adverse interest rate movements. In order to attempt to mitigate a portion of such risk, we utilize certain hedging techniques to attempt to lock in a portion of the net interest spread between the interest we earn on our assets and the interest we pay on our financing costs.
Additionally, because prepayments on residential mortgages generally accelerate when interest rates decrease and slow when interest rates increase, mortgage securities typically have "negative convexity." In other words, certain mortgage securities in which we invest may increase in price more slowly than similar duration bonds, or even fall in value, as interest rates decline. Conversely, certain mortgage securities in which we invest may decrease in value more quickly than similar duration bonds as interest rates increase. In order to manage this risk, we monitor, among other things, the "duration gap" between our mortgage assets and our hedge portfolio as well as our convexity exposure. Duration is the estimated percentage change in market value of our mortgage assets or our hedge portfolio that would be caused by a parallel change in short and long-term interest rates. Convexity exposure relates to the way the duration of our mortgage assets or our hedge portfolio changes when the interest rate or prepayment environment changes.
The value of our mortgage assets may also be adversely impacted by fluctuations in the shape of the yield curve or by changes in the market's expectation about the volatility of future interest rates. We analyze our exposure to non-parallel changes in interest rates and to changes in the market's expectation of future interest rate volatility and take actions to attempt to mitigate these risks.
Prepayment Risk. Because residential borrowers have the option to prepay their mortgage loans at par at any time, we face the risk that we will experience a return of principal on our investments faster than anticipated. Prepayment risk generally increases when interest rates decline. In this scenario, our financial results may be adversely affected as we may have to invest that principal at potentially lower yields.