Interactive Brokers Group, Inc.
MX ˙ BMV ˙ US45841N1072
SecurityMX:IBKR / Interactive Brokers Group, Inc.
InstitutionMarathon Asset Mgmt Ltd
Latest Disclosed Ownership543,043 shares
Latest Disclosed Value $ 36,420,844
Marathon Asset Mgmt Ltd reports 13.74% increase in ownership of IBKR / Interactive Brokers Group, Inc.

On April 24, 2026 - Marathon Asset Mgmt Ltd filed a 13F-HR form disclosing ownership of 543,043 shares of Interactive Brokers Group, Inc. (MX:IBKR) valued at $36,420,844 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 6, 2026 disclosing 477,442 shares of Interactive Brokers Group, Inc.. This represents a change in shares of 13.74% during the quarter.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-04-24 2026-03-31 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 543,043 65,601 13.74 36,421 18.62 1.3967
2026-02-06 2025-12-31 13F Interactive Brokers GRO-CL A COMMON 45841N107 477,442 -47,411 -9.03 30,705 -14.98 1.1813
2025-10-17 2025-09-30 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 524,853 -195,051 -27.09 36,115 -9.46 1.3288
2025-08-11 2025-06-30 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 719,904 537,366 294.39 39,889 31.97 1.2794
2025-04-24 2025-03-31 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 182,538 -76,562 -29.55 30,226 -33.97 0.9239
2025-02-06 2024-12-31 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 259,100 -16,756 -6.07 45,773 19.07 1.2787
2024-10-17 2024-09-30 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 275,856 -29,121 -9.55 38,443 2.82 1.0621
2024-08-14 2024-06-30 13F INTERACTIVE BROKERS GROUP IN COMMON 45841N107 304,977 304,977 37,390 1.1713
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.