Investments

At December 31, 2017 and December 31, 2016, the Company held investments classified as available-for-sale and investments classified as trading securities. Investments classified as available-for-sale consisted of municipal bonds with an amortized cost basis of $54.3 million and an investment in the redeemable preferred stock of a privately-held electrical utility substation security provider with an amortized cost basis of $5.0 million. The investment in redeemable preferred stock was classified in Level 3 of the fair value hierarchy and had a fair value of $4.1 million and $3.8 million at December 31, 2017 and 2016, respectively. Investments classified as trading securities were comprised primarily of debt and equity mutual funds and are stated at fair market value based on current quotes.

The following table sets forth selected data with respect to the Company’s investments at December 31, (in millions):



	2017											2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Carrying Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value		Carrying Value
Available-for-sale securities	$	59.3	$	0.1	$	(1.0	)	$	58.4	$	58.4	$	58.6	$	0.3	$	(1.5	)	$	57.4	$	57.4
Trading securities	8.9		4.9		—			13.8		13.8		7.1		3.1		—			10.2		10.2
TOTAL INVESTMENTS	$	68.2	$	5.0	$	(1.0	)	$	72.2	$	72.2	$	65.7	$	3.4	$	(1.5	)	$	67.6	$	67.6

Contractual maturities of our investments in available-for-sale securities at December 31, 2017 were as follows (in millions):



	Amortized Cost		Fair Value
Available-for-sale securities
Due within 1 year	$	14.5	$	14.5
After 1 year but within 5 years	31.5		30.7
After 5 years but within 10 years	10.9		10.8
Due after 10 years	2.4		2.4
TOTAL	$	59.3	$	58.4

The total unrealized gain/(loss) recognized in the year relating to available-for-sale securities, net of tax, was $0.6 million and $(0.9) million at December 31, 2017 and 2016, respectively. These net unrealized gains/(losses) are included in Accumulated other comprehensive loss, net of tax. Net unrealized gains relating to trading securities have been reflected in the results of operations. The Company uses the specific identification method when identifying the cost basis used to calculate the gain or loss on these securities. Gains and losses for both available-for-sale and trading securities were not material in 2017, 2016 and 2015.