The fair value of the Warehouse receivables is based on already locked-in security-buy prices. See Note 1, Interim Information, for additional discussion on our election of the fair value option for Warehouse receivables. As of September 30, 2017 and December 31, 2016, all of our Warehouse receivables included in our Condensed Consolidated Balance Sheet were under commitment to be purchased by government-sponsored enterprises ("GSEs") or by a qualifying investor as part of a U.S. government or GSE mortgage-backed security program. The Warehouse receivables are classified as Level 2 in the fair value hierarchy as all significant inputs are readily observable.
Deferred Compensation Plan
We maintain a deferred compensation plan for certain of our U.S. employees that allows them to defer portions of their compensation. We invest directly in insurance contracts which yield returns to fund these deferred compensation obligations. We recognize an asset for the amount that could be realized under these insurance contracts as of the balance sheet date, and we adjust the deferred compensation obligation to reflect the changes in the fair value of the amount owed to the employees. The inputs for this valuation are Level 2 inputs in the fair value hierarchy. We recorded this plan on our Condensed Consolidated Balance Sheet as of September 30, 2017, as Deferred compensation plan assets of $218.5 million, long-term deferred compensation plan liabilities of $208.8 million, included in Deferred compensation, and as a reduction of equity, Shares held in trust, of $5.8 million. We recorded this plan on our Condensed Consolidated Balance Sheet as of December 31, 2016, as Deferred compensation plan assets of $173.0 million, long-term deferred compensation plan liabilities of $169.5 million, included in Deferred compensation, and as a reduction of equity, Shares held in trust, of $6.0 million.
We classify our Earn-out liabilities within Level 3 in the fair value hierarchy because the inputs we use to develop the estimated fair value include unobservable inputs. We base the fair value of our Earn-out liabilities on the present value of probability-weighted future cash flows related to the earn-out performance criteria on each reporting date. We determine the probability of achievement we assign to the performance criteria based on the due diligence we performed at the time of acquisition as well as actual performance achieved subsequent to acquisition. An increase to the probability of achievement would result in a higher fair value measurement. See Note 4, Business Combinations, Goodwill and Intangibles, for additional discussion of our Earn-out liabilities.
Mortgage Banking Derivatives
The fair value of our rate lock commitments to prospective borrowers and the related inputs primarily include, as applicable, the expected net cash flows associated with servicing the loan and the effects of interest rate movements between the date of the interest rate lock commitment ("IRLC") and the balance sheet date based on applicable published U.S. Treasury rates.
The fair value of our forward sales contracts to prospective investors considers the market price movement of a similar security between the trade date and the balance sheet date. The market price changes are multiplied by the notional amount of the forward sales contracts to measure the fair value.
Both the rate lock commitments to prospective borrowers and the forward sale contracts to prospective investors are undesignated derivatives and considered Level 3 valuations due to significant unobservable inputs related to counterparty credit risk. An increase in counterparty credit risk assumptions would result in a lower fair value measurement. The fair valuation is determined using discounted cash flow techniques, and the derivatives are marked to fair value through Revenue in the Condensed Consolidated Statements on Comprehensive Income.