Discontinuation of hedge accounting for interest rate swap agreements
Prior to fiscal year 2011, we entered into interest rate swap agreements typically with the intention of qualifying for hedge accounting under ASC 815. However, during fiscal year 2011, we elected to discontinue hedge accounting for our interest rate swaps. Upon discontinuation of hedge accounting, the net deferred loss related to our de-designated interest rate swaps remained in accumulated OCI and was reclassified from accumulated OCI into interest expense on a straight-line basis over the remaining term of each interest rate swap through December 2016.
Interest rate swap agreements
We use interest rate swaps to hedge the variable cash flows associated with our borrowings made under repurchase agreements. Under our interest rate swap agreements, we typically pay a fixed rate and receive a floating rate based on one, three or six-month LIBOR ("payer swaps") with terms up to 20 years. Our swap agreements are privately negotiated in the over−the−counter ("OTC") market.
Swap agreements entered into after May 2013 are centrally cleared through a registered commodities exchange. We value centrally cleared interest rate swaps using the daily settlement price, or fair value, determined by the clearing exchange based on a pricing model that references observable market inputs, including LIBOR, swap rates and the forward yield curve. Our centrally cleared swaps require that we post an "initial margin" amount determined by the clearing exchange, which is generally intended to be set at a level sufficient to protect the exchange from the interest rate swap's maximum estimated single-day price movement. We also exchange "variation margin" based upon daily changes in fair value, as measured by the exchange. As a result of amendments to rules governing certain central clearing activities, which took effect January 3, 2017, the exchange of variation margin is a settlement of the interest rate swap, as opposed to pledged collateral. Accordingly, beginning in the first quarter of 2017 and in subsequent periods, we account for the receipt or payment of variation margin as a direct reduction to the carrying value of the interest rate swap asset or liability. Variation margin pledged / (received) was previously reported in restricted cash and cash equivalents / (other liabilities) in our consolidated balance sheet.
We value non-centrally cleared swaps using a combination of third-party valuations obtained from pricing services and the swap counterparty. The third-party valuations are model-driven using observable inputs, including LIBOR, swap rates and the forward yield curve. We also consider both our own and our counterparties' nonperformance risk in estimating the fair value of our interest rate swaps. In considering the effect of nonperformance risk, we assess the impact of netting and credit enhancements, such as collateral postings and guarantees, and have concluded that our own and our counterparty risk is not significant to the overall valuation of these agreements.
Interest rate swaptions
We purchase interest rate swaptions to help mitigate the potential impact of larger, more rapid changes in interest rates on the performance of our investment portfolio. Interest rate swaptions provide us the option to enter into an interest rate swap agreement for a predetermined notional amount, stated term and pay and receive interest rates in the future. Our swaption agreements typically provide us the option to enter into a pay-fixed rate interest rate swap ("payer swaptions"). We may also enter into swaption agreements that provide us the option to enter into a receive-fixed interest rate swap ("receiver swaptions").
Our interest rate swaption agreements are privately negotiated in the OTC market and are not subject to central clearing. The premium paid for interest rate swaptions is reported as an asset in our consolidated balance sheets. We estimate the fair value of interest rate swaptions using a combination of inputs from counterparty and third-party pricing models based on the fair value of the future interest rate swap that we have the option to enter into as well as the remaining length of time that we have to exercise the option, adjusted for non-performance risk, if any. The difference between the premium paid and the fair value of the swaption is reported in gain (loss) on derivative instruments and other securities, net in our consolidated statements of comprehensive income. If a swaption expires unexercised, the realized loss on the swaption would be equal to the premium paid. If we sell or exercise a swaption, the realized gain or loss on the swaption would be equal to the difference between the cash or the fair value of the underlying interest rate swap received and the premium paid.
A TBA security is a forward contract for the purchase or sale of Agency RMBS at a predetermined price, face amount, issuer, coupon and stated maturity on an agreed-upon future date. The specific Agency RMBS to be delivered into the contract are not known until shortly before the settlement date. We may choose, prior to settlement, to move the settlement of these securities out to a later date by entering into an offsetting TBA position, net settling the offsetting positions for cash, and simultaneously purchasing or selling a similar TBA contract for a later settlement date (together referred to as a "dollar roll transaction"). The Agency securities purchased or sold for a forward settlement date are typically priced at a discount to equivalent securities settling in the current month. This difference, or "price drop," is the economic equivalent to interest income on the underlying Agency securities, less