Our marketable securities consist of investments in the publicly-traded shares of our immediate parent company Valhi, Inc. Our shares of Valhi common stock are accounted for as available-for-sale securities, which are carried at fair value using quoted market prices in active markets and represent a Level 1 input within the fair value hierarchy. Any unrealized gains or losses on the securities are recognized in Marketable equity securities on our Condensed Consolidated Statements of Income.

	Fair value measurement level	Market value		Cost basis		Unrealized gain (loss)
		(In thousands)
December 31, 2020
Valhi common stock	1	$	18,206	$	24,347	$	(6,141	)

March 31, 2021
Valhi common stock	1	$	24,566	$	24,347	$	219

At December 31, 2020 and March 31, 2021, we held approximately 1.2 million shares of common stock of our immediate parent company, Valhi, Inc. At December 31, 2020 and March 31, 2021, the quoted per share market price of Valhi common stock was $15.20 and $20.51, respectively.

The Valhi common stock we own is subject to restrictions on resale pursuant to certain provisions of the SEC Rule 144. In addition, as a majority-owned subsidiary of Valhi, we cannot vote our shares of Valhi common stock under Delaware General Corporation Law, but we receive dividends from Valhi on these shares, when declared and paid.