The carrying value of our cash and cash equivalents, restricted cash, accounts receivable and accounts payable approximate fair value because of their short-term nature.

Our held-to-maturity investments are comprised of U.S. Treasury securities and a corporate debt security, which are held at amortized cost. We also have an investment in a convertible note receivable which is held at fair value. Additionally, we maintain a deferred compensation plan with related assets held in a rabbi trust.

The following tables show our cash, cash equivalents, and debt investments by significant investment category as of June 30, 2023 and December 31, 2022:



	June 30, 2023
	Adjusted cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Current Investments		Long-term Investments
Cash	$	68,473	$	-	$	-	$	68,473	$	68,473	$	-	$	-
Level 1⁽¹⁾
Money market funds		360,901		-		-		360,901		360,901		-		-
Time deposits		75,492		-		-		75,492		75,492		-		-
U.S. Treasury securities		1,218,648		265		11,461		1,207,452		-		850,443		368,205
Subtotal		1,655,042		265		11,461		1,643,846		436,393		850,443		368,205
Level 3
Corporate debt security⁽²⁾		17,700		-		461		17,239		-		699		17,001
Note receivable⁽³⁾		4,860		284		-		5,144		-		-		5,144
Subtotal		22,560		284		461		22,383		-		699		22,145
Total	$	1,746,075	$	549	$	11,922	$	1,734,702	$	504,866	$	851,142	$	390,350

	December 31, 2022
	Adjusted cost		Unrealized Gains		Unrealized Losses		Fair Value		Cash and Cash Equivalents		Current Investments		Long-term Investments
Cash	$	75,829	$	-	$	-	$	75,829	$	75,829	$	-	$	-
Level 1⁽¹⁾
Money market funds		232,477		-		-		232,477		232,477		-		-
Time deposits		75,694		-		-		75,694		75,694		-		-
U.S. Treasury securities		847,354		63		14,355		833,062		-		515,136		332,218
Subtotal		1,155,525		63		14,355		1,141,233		308,171		515,136		332,218
Level 3
Corporate debt security⁽²⁾		17,900		-		700		17,200		-		-		17,900
Note receivable⁽³⁾		4,860		222		-		5,082		-		-		5,082
Subtotal		22,760		222		700		22,282		-		-		22,982
Total	$	1,254,114	$	285	$	15,055	$	1,239,344	$	384,000	$	515,136	$	355,200

⁽¹⁾ Level 1: Quoted prices in active markets for identical assets or liabilities that the entity has the ability to access.

⁽²⁾ The fair value of the corporate debt security is measured using Level 3 (unobservable) inputs. We determined the fair value for the corporate debt security using an internally-developed valuation model and unobservable inputs include credit and liquidity spreads and effective maturity.

⁽³⁾ We have elected to measure our investment in a convertible note receivable of a private company at fair value under the fair value option. The fair value of the note receivable is measured using Level 3 (unobservable) inputs. We determined the fair value for the note receivable using an internally-developed valuation model and unobservable inputs include estimates of the equity value of the underlying business and the timing and probability of future financing events.

Rabbi Trust

We have elected to fund certain deferred compensation plan obligations through a rabbi trust, the assets of which are designated as trading securities. The rabbi trust is subject to creditor claims in the event of insolvency, but the assets held in the rabbi trust are not available for general corporate purposes. Amounts in the rabbi trust are invested in mutual funds, consistent with the investment choices selected by participants in their Deferred Plan accounts, which are designated as trading securities, carried at fair value and are included in other assets on the condensed consolidated balance sheets. We record trading gains and losses, along with the offsetting amount related to the increase or decrease in deferred compensation to reflect our exposure to liabilities for payment under the deferred plan in general and administrative expenses on the condensed consolidated statements of income and comprehensive income.

Assets recognized or disclosed at fair value on the condensed consolidated financial statements on a nonrecurring basis include items such as leasehold improvements, property and equipment, certain long-term investments, operating lease assets, other assets, and goodwill. These assets are measured at fair value whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable or if there has been an observable price change of a non-marketable equity security.

The following table summarizes our restaurant and office assets measured at fair value by hierarchy level on a nonrecurring basis: