HELD-TO-MATURITY INVESTMENTS

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

A summary of the Company’s held-to-maturity investments is presented below:


	SEPTEMBER 30, 2021
DESCRIPTION	AMORTIZED COST		GROSS UNREALIZED HOLDING GAINS		GROSS UNREALIZED HOLDING LOSSES		FAIR VALUE

U.S. Treasury securities maturing in one year or less	$	399,753	$	40	$	(1)	$	399,792
U.S. Treasury securities maturing in greater than one year	81,084		—		(16)		81,068
Total	$	480,837	$	40	$	(17)	$	480,860


	DECEMBER 31, 2020
DESCRIPTION	AMORTIZED COST		GROSS UNREALIZED HOLDING GAINS		GROSS UNREALIZED HOLDING LOSSES		FAIR VALUE

U.S. Treasury securities maturing in one year or less	$	442,820	$	163	$	(12)	$	442,971

The Company’s policy is not to measure an allowance for credit losses for interest receivable and to write off any uncollectible interest receivable as a reversal of interest income in the period in which it determines the interest will not be collected. The Company did not write off any interest receivable during the three and nine months ended September 30, 2021 and 2020.

The contractual terms of these investments do not permit the issuer to settle the securities at a price less than the amortized cost bases of the investments. The Company does not intend to sell its investments and has the intent and ability to hold its investments until they mature.

Dicerna Pharmaceuticals Inc 10-Q