Question 1

How many shares of IBKR does CANTILLON CAPITAL MANAGEMENT LLC own?

Accepted Answer

As of 2026-Q2, CANTILLON CAPITAL MANAGEMENT LLC holds 517,833 shares of IBKR (INTERACTIVE BROKERS GRO-CL A).

Question 2

What is CANTILLON CAPITAL MANAGEMENT LLC's IBKR position worth?

Accepted Answer

As of 2026-Q2, CANTILLON CAPITAL MANAGEMENT LLC's IBKR position is worth $45.1M.

Question 3

Is CANTILLON CAPITAL MANAGEMENT LLC buying or selling IBKR?

Accepted Answer

In 2026-Q2, CANTILLON CAPITAL MANAGEMENT LLC decreased their IBKR position (-95.4% change in shares).

Question 4

When did CANTILLON CAPITAL MANAGEMENT LLC first buy IBKR?

Accepted Answer

Based on available 13F filings, CANTILLON CAPITAL MANAGEMENT LLC first reported a position in IBKR in 2024-Q3. They have held the position across 30 quarters.

Quarter	Action	Shares	Change	Value	Weight	Price	Conviction
2026-Q2 Latest	Decreased	517,833	-95.4%	$45.1M	6.8%	$87.04	0
2026-Q1	Decreased	11.2M	-11.9%	$754.3M	5.0%	$69.40	0
2025-Q4	Increased	12.8M	+0.8%	$820.6M	4.4%	$65.00	60
2025-Q3	Decreased	12.7M	-1.1%	$871.4M	4.8%	$68.72	0
2025-Q2	Increased	12.8M	+288.7%	$709.4M	4.1%	$53.82	95
2025-Q1	Decreased	3.3M	-3.0%	$545.4M	3.5%	$41.01	0
2024-Q4	Increased	3.4M	+0.5%	$599.9M	3.6%	$44.50	59
2024-Q3	Decreased	3.4M	-2.9%	$470.7M	2.9%	$34.16	0