
	June 27, 2021
(in millions of U.S. Dollars)	Amortized Cost	Gross Unrealized Gains	Gross Unrealized Losses	Estimated Fair Value
Municipal bonds	$139.4	$1.9	$—	$141.3
Corporate bonds	456.5	3.3	(0.3)	459.5
U.S. agency securities	15.8	—	—	15.8
U.S. treasury securities	72.3	0.3	(0.1)	72.5
Certificates of deposit	16.5	—	—	16.5

Commercial paper	50.0	—	—	50.0
Variable rate demand note	20.0	—	—	20.0

Total short-term investments	$770.5	$5.5	($0.4)	$775.6

The following table presents the gross unrealized losses and estimated fair value of the Company’s short-term investments, aggregated by investment type and the length of time that individual securities have been in a continuous unrealized loss position:


	June 27, 2021
	Less than 12 Months		Greater than 12 Months		Total
(in millions of U.S. Dollars)	Fair Value	Unrealized Loss	Fair Value	Unrealized Loss	Fair Value	Unrealized Loss
Municipal bonds	$28.8	$—	$—	$—	$28.8	$—
Corporate bonds	133.8	(0.3)	—	—	133.8	(0.3)
U.S. agency securities	16.7	—	—	—	16.7	—
U.S. treasury securities	47.9	(0.1)	—	—	47.9	(0.1)
Certificates of deposit	0.7	—	—	—	0.7	—

Total	$227.9	($0.4)	$—	$—	$227.9	($0.4)
Number of securities with an unrealized loss		134		—		134


	June 28, 2020
(in millions of U.S. Dollars)	Amortized Cost	Gross Unrealized Gains	Gross Unrealized Losses (1)	Estimated Fair Value
Municipal bonds	130.0	2.0	—	132.0
Corporate bonds	473.8	6.3	—	480.1
U.S. agency securities	29.1	—	—	29.1
U.S. treasury securities	52.3	0.6	—	52.9
Certificates of deposit	83.3	—	—	83.3

Commercial paper	11.0	—	—	11.0
Variable rate demand note	2.5	—	—	2.5
Total short-term investments	782.0	8.9	—	790.9


	June 28, 2020
	Less than 12 Months		Greater than 12 Months		Total
(in millions of U.S. Dollars)	Fair Value	Unrealized Loss (1)	Fair Value	Unrealized Loss	Fair Value	Unrealized Loss
Municipal bonds	$14.3	$—	$—	$—	$14.3	$—
Corporate bonds	29.1	—	—	—	29.1	—
U.S. agency securities	8.6	—	—	—	8.6	—
U.S. treasury securities	13.8	—	—	—	13.8	—


Total	$65.8	$—	$—	$—	$65.8	$—
Number of securities with an unrealized loss		46		—		46

(1) Securities with an unrealized loss of less than 12 months as of June 28, 2020 had an unrealized loss value of less than $0.1 million, individually and in the aggregate.

The Company does not include accrued interest in estimated fair values of short-term investments and does not record an allowance for credit losses on receivables related to accrued interest. Accrued interest receivable was $5.5 million and $4.3 million as of June 27, 2021 and June 28, 2020, respectively, and is recorded in other current assets on the consolidated balance sheets. When necessary, write-offs of noncollectable interest income are recorded as a reversal to interest income. There were no write-offs of noncollectable interest income for the years ended June 27, 2021 and June 28, 2020.

The Company utilizes specific identification in computing realized gains and losses on the sale of investments. Realized gains and losses are included in non-operating expense (income), net in the consolidated statements of operations. Unrealized gains and losses are included as a separate component of equity, net of tax, unless the Company determines there is an expected credit loss.

The Company evaluates its investments for expected credit losses. The Company believes it is able to and intends to hold each of the investments held with an unrealized loss as of June 27, 2021 until the investments fully recover in market value. No allowance for credit losses was recorded as of June 27, 2021.


(in millions of U.S. Dollars)	Within One Year	After One, Within Five Years	After Five, Within Ten Years	After Ten Years	Total
Municipal bonds	$24.7	$116.6	$—	$—	$141.3
Corporate bonds	80.3	379.2	—	—	459.5
U.S. agency securities	3.5	12.3	—	—	15.8
U.S. treasury securities	24.7	47.8	—	—	72.5
Certificates of deposit	16.5	—	—	—	16.5

Commercial paper	50.0	—	—	—	50.0
Variable rate demand note	—	—	—	20.0	20.0

Total short-term investments	$199.7	$555.9	$—	$20.0	$775.6