Investments consist of the following as of December 31, 2023 and 2022 (dollars in thousands):


	December 31, 2023
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available for sale):
Non-governmental debt securities	$	245,886	$	719	$	(892	)	$	245,713
Treasury and federal agencies		239,859		393		(830	)		239,422
Total short-term investments (available for sale)	$	485,745	$	1,112	$	(1,722	)	$	485,135


	December 31, 2022
			Gross Unrealized
	Cost		Gain		(Loss)			Fair Value
Short-term investments (available for sale):
Municipal bonds	$	3,016	$	-	$	(22	)	$	2,994
Non-governmental debt securities		222,575		37		(2,880	)		219,732
Treasury and federal agencies		179,068		6		(2,485	)		176,589
Total short-term investments (available for sale)	$	404,659	$	43	$	(5,387	)	$	399,315

In the table above, unrealized holding gains (losses) relate to short-term investments that have been in a continuous unrealized gain (loss) position for less than one year.

Our non-governmental debt securities primarily consist of corporate bonds, certificates of deposit and commercial paper. Our treasury and federal agencies primarily consist of U.S. Treasury bills and federal home loan debt securities.

A schedule of available-for-sale investments segregated by their original stated terms to maturity as of December 31, 2023 and 2022 are as follows (dollars in thousands):


	Less than one year		One to five years		Total
Original stated term to maturity of available-for-sale- investments as of December 31, 2023	$	251,070	$	234,065	$	485,135
Original stated term to maturity of available-for-sale- investments as of December 31, 2022	$	188,472	$	210,843	$	399,315

Realized gains or losses resulting from sales of investments were zero during the years ended December 31, 2023 and 2022 and realized losses were less than $0.1 million for the year ended December 31, 2021.

FASB ASC Topic 820 – Fair Value Measurements establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions.

As of December 31, 2023 and 2022, we held investments that are required to be measured at fair value on a recurring basis. These investments (available for sale) consist of municipal bonds, non-governmental debt securities and treasury and federal agencies securities. Available for sale securities included in Level 2 are estimated based on observable inputs other than quoted prices in active markets for identical assets and liabilities, such as quoted prices for identical or similar assets or liabilities in inactive markets or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

All of our available for sale investments were measured under Level 2 as of December 31, 2023 and December 31, 2022. Additionally, money market funds of $30.3 million and $40.1 million included within cash and cash equivalents on our consolidated balance sheets as of December 31, 2023 and 2022, respectively, were measured under Level 1. Federal agency debt securities of $44.9 million included within cash and cash equivalents on our consolidated balance sheets as of December 31, 2023 were measured under Level 2.

Our investment in an equity affiliate, which is recorded within other noncurrent assets on our consolidated balance sheets, represents an international investment in a private company. As of December 31, 2023, our investment in an equity affiliate equated to a 30.7%, or $1.2 million.

We recorded a gain of less than $0.1 million for the year ended December 31, 2023, related to our equity affiliate within miscellaneous income (expense) on our consolidated statements of income. For the years ended December 31, 2022 and 2021, we recorded approximately $1.8 million of loss and $0.2 million of gain, respectively, related to our equity affiliate within miscellaneous income (expense) on our consolidated statements of income. The 2022 loss included $1.2 million related to an impairment of our equity affiliate due to decline in projected cash flows.