SHORT-TERM INVESTMENTS: (Tables)

9 Months Ended

Sep. 30, 2024

SHORT-TERM INVESTMENTS:

Schedule of short-term investments

Short-term investments were as follows (in millions):

	At September 30,			At December 31,
	2024			2023
Trading securities	$	318.6		$	599.1
Weighted average interest rate		5.5	%		5.7	%
Available-for-sale	$	0.2		$	0.2
Weighted average interest rate		0.8	%		0.8	%
Total	$	318.8		$	599.3

Summary of activity investments

The following table summarizes the activity of these investments by category (in millions):

	Three months ended				Nine months ended
	September 30,				September 30,
	2024		2023		2024		2023
Trading:
Interest earned	$	8.0	$	3.3	$	18.6	$	7.6
Unrealized gain (loss) at the end of the period	$	(*)	$	(*)	$	(*)	$	(*)
Available-for-sale:
Interest earned	$	(*)	$	(*)	$	(*)	$	(*)
Investment redeemed	$	—	$	—	$	—	$	—

(*) Less than $0.1 million.