Investments (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2021

Dec. 31, 2020

Investments

Amortized cost and fair values

The following tables present cost or amortized cost and fair values of investment in fixed maturities as of September 30, 2021 and December 31, 2020 ($ in millions):

			Gross Unrealized				Fair
	Cost or Amortized Cost		Gains		Losses		Value
September 30, 2021
Corporate debt securities	$	588.0	$	—	$	(0.9)	$	587.1
U.S. Government obligations		110.0		0.1		(0.2)		109.9
Municipal securities		0.6		—		—		0.6
Total	$	698.6	$	0.1	$	(1.1)	$	697.6
December 31, 2020
Corporate debt securities	$	—	$	—	$	—	$	—
U.S. Government obligations		6.4		0.2		—		6.6
Municipal securities		—		—		—		—
Total	$	6.4	$	0.2	$	—	$	6.6

The following tables present cost or amortized cost and fair values of investments at December 31, 2020 and 2019, respectively ($ in millions):

	Cost or		Gross
	Amortized		Unrealized				Fair
	Cost		Gains		Losses		Value
December 31, 2020
U.S. Government obligations	$	6.4	$	0.2	$	—	$	6.6
Total	$	6.4	$	0.2	$	—	$	6.6
December 31, 2019
U.S. Government obligations	$	5.8	$	0.1	$	—	$	5.9
Total	$	5.8	$	0.1	$	—	$	5.9

Contractual maturities of bonds

The following table presents the cost or amortized cost and estimated fair value of investments in fixed maturities as of September 30, 2021 by contractual maturity ($ in millions). Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	September 30, 2021
	Cost or
	Amortized
	Cost		Fair Value
Due in one year or less	$	31.0	$	31.0
Due after one year through five years		667.6		666.6
Due after five years through ten years		—		—
Due after ten years		—		—
Total	$	698.6	$	697.6

The following table presents the cost or amortized cost and estimated fair value of bonds as of December 31, 2020 by contractual maturity ($ in millions). Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	December 31, 2020
	Cost or
	Amortized
	Cost		Fair Value
Due in one year or less	$	—	$	—
Due after one year through five years		6.4		6.6
Due after five years through ten years		—		—
Due after ten years		—		—
Total	$	6.4	$	6.6

Aging of gross unrealized losses

The following table presents the gross unrealized losses and related fair values for the Company’s investment in fixed maturities, grouped by duration of time in a continuous unrealized loss position as of September 30, 2021 and December 31, 2020 ($ in millions):

	Less than 12 Months				12 Months or More				Total
	Gross Unrealized				Gross Unrealized				Gross Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
September 30, 2021
Corporate debt securities	$	504.8	$	(0.9)	$	—	$	—	$	504.8	$	(0.9)
U.S. Government obligations		103.9		(0.2)		—		—		103.9		(0.2)
Municipal securities		—		—		—		—		—		—
Total	$	608.7	$	(1.1)	$	—	$	—	$	608.7	$	(1.1)

Less than 12 Months

12 Months or More

Total

Gross Unrealized

Gross Unrealized

Gross Unrealized

Fair Value

Losses

Fair Value

Losses

Fair Value

Losses

December 31, 2020

Corporate debt securities

$

—

$

—

$

—

$

—

$

—

$

—

U.S. Government obligations

—

—

—

—

—

—

Municipal securities

—

—

—

—

—

—

Total

$

—

$

—

$

—

$

—

$

—

$

—

The following tables present the gross unrealized losses and related fair values for the Company’s available-for-sale bond securities, grouped by duration of time in a continuous unrealized loss position, as of December 31, 2020 and 2019 ($ in millions):

	Less than 12 Months				12 Months or More				Total
			Gross				Gross				Gross
			Unrealized				Unrealized				Unrealized
	Fair Value		Losses		Fair Value		Losses		Fair Value		Losses
December 31, 2020
U.S. Government obligations	$	—	$	—	$	—	$	—	$	—	$	—
Total	$	—	$	—	$	—	$	—	$	—	$	—
December 31, 2019
U.S. Government obligations	$	0.2	$	—	$	2.2	$	—	$	2.4	$	—
Total	$	0.2	$	—	$	2.2	$	—	$	2.4	$	—

Special deposits

	December 31,
U.S. State	2020		2019
New York	$	2.8	$	2.1
Washington		1.2		1.1
Colorado		1.1		1.1
North Carolina		0.3		0.3
New Mexico		0.3		0.3
Virginia		0.3		0.3
Florida		0.2		—
Nevada		0.2		0.2
Arkansas		—		0.1
Massachusetts		0.1		0.1
Total	$	6.5	$	5.6

Net investment income

An analysis of net investment income follows ($ in millions):

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2021		2020		2021		2020
Interest on cash and cash equivalents	$	0.1	$	0.1	$	0.4	$	0.9
Fixed maturities		0.6		0.1		0.7		0.1
Short-term investments		—		—		—		0.3
		0.7	$	0.2		1.1		1.3
Investment expense		0.1		—		0.1		—
Net investment income	$	0.6	$	0.2	$	1.0	$	1.3

An analysis of net investment income follows ($ in millions):

	December 31,
	2020		2019		2018
Interest on cash and cash equivalents	$	1.0	$	2.8	$	1.0
Bonds		0.1		0.1		0.1
Short-term investments		0.4		0.5		0.2
Net investment income	$	1.5	$	3.4	$	1.3