Mainstream Capital Management LLC

Position in IBKR — Interactive Brokers Group, Inc.

CIK 2043084 LOS ANGELES, CA

Position in IBKR

as of Jun 30, 2026 · filed Jul 15, 2026 Compact

Position Value

$1,908,177

+$445,113 QoQ

Shares Held

21,923

+0.5% QoQ

Ownership

0.005%

of shares outstanding

% of Portfolio

2.02%

of 13F equity value

Holder Rank

#468

of 1,105 holders

Holding Since

Mar 2025

6 quarters on record

Voting authority Sole 100% Shared 0% None 0%

Financial Services · as of Jun 30, 2026

Mainstream Capital Management LLC holds $5,755,069 across 4 Capital Markets names. IBKR ranks #2 (33.2% of the industry book) .

#	Ticker	Company	Shares	Value (USD)
1	GS	Goldman Sachs Group Inc	1,890	$1,911,489
2	IBKR	Interactive Brokers Group, Inc. This page	21,923	$1,908,177
3	SCHW	Schwab Charles Corp	16,030	$1,479,088
4	RIOT	Riot Platforms, Inc.	16,666	$456,315

6 filing rows on record

Report Date	Value (USD)	Shares	Change	Type	Discretion	Filed
2026-06-30	$1,908,177	21,923	+0.5%	Shares	Sole	2026-07-15
2026-03-31	$1,463,064	21,814	+1.2%	Shares	Sole	2026-04-17
2025-12-31	$1,386,009	21,552	+11.2%	Shares	Sole	2026-01-21
2025-09-30	$1,333,606	19,381	+5.5%	Shares	Sole	2025-10-20
2025-06-30	$1,017,992	18,372	+327.2%	Shares	Sole	2025-07-15
2025-03-31	$712,202	4,301	—	Shares	Sole	2025-04-28
No filing history on record for this holder in this stock.