Fair value estimates are dependent upon subjective assumptions and involve significant uncertainties resulting in variability in estimates with changes in assumptions. The following table summarizes the principal amounts, carrying values and the estimated fair values of our financial instruments (in thousands):

Assets and liabilities disclosed at fair value are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Determining which category an asset or liability falls within the hierarchy requires judgment and we evaluate our hierarchy disclosures each quarter. Hierarchical levels directly related to the amount of subjectivity associated with the inputs to fair valuation of these assets and liabilities are as follows:

Level 1—Inputs are unadjusted and quoted prices exist in active markets for identical assets or liabilities, such as government, agency and equity securities.

Level 2—Inputs (other than quoted prices included in Level 1) are observable for the asset or liability through correlation with market data. Level 2 inputs may include quoted market prices for a similar asset or liability, interest rates and credit risk. Examples include non-government securities, certain mortgage and asset-backed securities, certain corporate debt and certain derivative instruments.

Level 3—Inputs reflect our best estimate of what market participants would use in pricing the asset or liability and are based on significant unobservable inputs that require a considerable amount of judgment and assumptions. Examples include certain mortgage and asset-backed securities, certain corporate debt and certain derivative instruments.

The following is a description of the valuation techniques used to measure fair value and the general classification of these instruments pursuant to the fair value hierarchy.

Loans and investments, net. Fair values of loans and investments that are not impaired are estimated using inputs based on direct capitalization rate and discounted cash flow methodologies using discount rates, which, in our opinion, best reflect current market interest rates that would be offered for loans with similar characteristics and credit quality (Level 3). Fair values of impaired loans and investments are estimated using inputs that require significant judgments, which include assumptions regarding discount rates, capitalization rates, creditworthiness of major tenants, occupancy rates, availability of financing, exit plans and other factors (Level 3).

Loans held-for-sale, net. Consists of originated loans that are generally expected to be transferred or sold within 60 days to 180 days of loan funding, and are valued using pricing models that incorporate observable inputs from current market assumptions or a hypothetical securitization model utilizing observable market data from recent securitization spreads and observable pricing of loans with similar characteristics (Level 2). Fair value includes the fair value allocated to the associated future MSRs and is calculated pursuant to the valuation techniques described below for capitalized mortgage servicing rights, net (Level 3).

Capitalized mortgage servicing rights, net. Fair values are estimated using inputs based on discounted future net cash flow methodology (Level 3). The fair value of MSRs carried at amortized cost are estimated using a process that involves the use of independent third-party valuation experts, supported by commercially available discounted cash flow models and analysis of current market data. The key inputs used in estimating fair value include the contractually specified servicing fees, prepayment speed of the underlying loans, discount rate, annual per loan cost to service loans, delinquency rates, late charges and other economic factors.

Securities held-to-maturity, net. Fair values are approximated using inputs based on current market quotes received from financial sources that trade such securities and are based on prevailing market data and, in some cases, are derived from third-party proprietary models based on well recognized financial principles and reasonable estimates about relevant future market conditions (Level 3).

Derivative financial instruments. Fair values of rate lock and forward sale commitments are estimated using valuation techniques, which include internally-developed models developed based on changes in the U.S. Treasury rate and other observable market data (Level 2). The fair value of rate lock commitments includes the fair value of the expected net cash flows associated with the servicing of the loans, see capitalized mortgage servicing rights, net above for details on the applicable valuation technique (Level 3). We also consider the impact of counterparty non-performance risk when measuring the fair value of these derivatives. Given the credit quality of our counterparties, the short duration of interest rate lock commitments and forward sale contracts, and our historical experience, the risk of nonperformance by our counterparties is not significant.

Credit and repurchase facilities. Fair values for credit and repurchase facilities of the Structured Business are estimated using discounted cash flow methodology, using discount rates, which, in our opinion, best reflect current market interest rates for financing with similar characteristics and credit quality (Level 3). The majority of our credit and repurchase facilities for the Agency Business bear interest at rates that are similar to those available in the market currently and fair values are estimated using Level 2 inputs. For these facilities, the fair values approximate their carrying values.

Collateralized loan obligations and junior subordinated notes. Fair values are estimated based on broker quotations, representing the discounted expected future cash flows at a yield that reflects current market interest rates and credit spreads (Level 3).

Senior unsecured notes. Fair values are estimated at current market quotes received from active markets when available (Level 1). If quotes from active markets are unavailable, then the fair values are estimated utilizing current market quotes received from inactive markets (Level 2).

Convertible senior unsecured notes, net. Fair values are estimated using current market quotes received from inactive markets (Level 2).

We measure certain financial assets and financial liabilities at fair value on a recurring basis. The fair values of these financial assets and liabilities are determined using the following input levels as of June 30, 2021 (in thousands):

We measure certain financial and non-financial assets at fair value on a nonrecurring basis. The fair values of these financial and non-financial assets, if applicable, are determined using the following input levels as of June 30, 2021 (in thousands):

(1)	We had an allowance for credit losses of $98.7 million relating to nine impaired loans with an aggregate carrying value, before loan loss reserves, of $165.7 million at June 30, 2021.

Loan impairment assessments. Loans held for investment are intended to be held to maturity and, accordingly, are carried at cost, net of unamortized loan origination costs and fees, loan purchase discounts, and net of the allowance for credit losses, when such loan or investment is deemed to be impaired. We consider a loan impaired when, based upon current information, it is probable that we will be unable to collect all amounts due for both principal and interest according to the contractual terms of the loan agreement. We evaluate our loans to determine if the value of the underlying collateral securing the impaired loan is less than the net carrying value of the loan, which may result in an allowance and corresponding charge to the provision for credit losses. These valuations require significant judgments, which include assumptions regarding capitalization and discount rates, revenue growth rates, creditworthiness of major tenants, occupancy rates, availability of financing, exit plan and other factors. The table above and below includes all impaired loans, regardless of the period in which the impairment was recognized.

Quantitative information about Level 3 fair value measurements at June 30, 2021 is as follows ($ in thousands):


			Valuation
	Fair Value		Techniques	Significant Unobservable Inputs
Financial assets:
Impaired loans:
Land	$	49,960	Discounted cash flows	Discount rate	21.50	%
				Revenue growth rate	3.00	%

				Discount rate	10.15	%
Retail		15,511	Discounted cash flows	Capitalization rate	9.25	%
				Revenue growth rate	1.68	%

Healthcare		828	Discounted cash flows	Capitalization rate	14.30	%

				Discount rate	11.00	%
Office		636	Discounted cash flows	Capitalization rate	9.00	%
				Revenue growth rate	2.50	%
Derivative financial instruments:
Rate lock commitments		124	Discounted cash flows	W/A discount rate	8.44	%

The derivative financial instruments using Level 3 inputs are outstanding for short periods of time (generally less than 60 days). A roll-forward of Level 3 derivative instruments is as follows (in thousands):


	Fair Value Measurements Using				Fair Value Measurements Using
	Significant Unobservable Inputs				Significant Unobservable Inputs
	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Derivative assets and liabilities, net
Beginning balance	$	1,439	$	2,069	$	1,967	$	1,066
Settlements		(23,045)		(33,936)		(58,074)		(54,867)
Realized gains recorded in earnings		21,606		31,867		56,107		53,801
Unrealized gains recorded in earnings		124		549		124		549
Ending balance	$	124	$	549	$	124	$	549

The components of fair value and other relevant information associated with our rate lock commitments, forward sales commitments and the estimated fair value of cash flows from servicing on loans held-for-sale are as follows (in thousands):


	Notional/		Fair Value of		Interest Rate		Total Fair Value
June 30, 2021	Principal Amount		Servicing Rights		Movement Effect		Adjustment
Rate lock commitments	$	16,550	$	124	$	127	$	251
Forward sale commitments		328,069		—		(127)		(127)
Loans held-for-sale, net (1)		448,940		9,669		—		9,669
Total			$	9,793	$	—	$	9,793

(1)	Loans held-for-sale, net are recorded at the lower of cost or market on an aggregate basis and includes fair value adjustments related to estimated cash flows from MSRs.

We measure certain assets and liabilities for which fair value is only disclosed. The fair value of these assets and liabilities are determined using the following input levels as of June 30, 2021 (in thousands):


					Fair Value Measurements Using Fair Value Hierarchy
	Carrying Value		Fair Value		Level 1		Level 2		Level 3
Financial assets:
Loans and investments, net	$	7,213,915	$	7,421,181	$	—	$	—	$	7,421,181
Loans held-for-sale, net		457,647		469,195		—		459,526		9,669
Capitalized mortgage servicing rights, net		418,653		471,275		—		—		471,275
Securities held-to-maturity, net		114,696		125,003		—		—		125,003

Financial liabilities:
Credit and repurchase facilities	$	2,015,188	$	2,016,291	$	—	$	391,790	$	1,624,501
Collateralized loan obligations		3,484,088		3,506,460		—		—		3,506,460
Senior unsecured notes		836,074		853,814		853,814		—		—
Convertible senior unsecured notes, net		270,917		304,689		—		304,689		—
Junior subordinated notes		142,013		100,650		—		—		100,650