Interactive Brokers (NASDAQ: IBKR) files prospectus to register 920,000 shares

Rhea-AI Filing Summary

Interactive Brokers Group, Inc. reported that on July 31, 2026 it filed a Prospectus Supplement under Rule 424(b)(5) relating to its shelf Registration Statement on Form S-3 (Registration No. 333-297857) to register up to 920,000 shares of its common stock, par value $0.01 per share.

A legal opinion from Dechert LLP concerning the validity of these shares was filed as Exhibit 5.3 and incorporated by reference into the Registration Statement. A Cover Page Interactive Data File was also included as Exhibit 104, with XBRL tags embedded in the Inline XBRL document.

Filing Explained

The 8-K records registration of up to 920,000 shares, creating issuance capacity without showing that shares were sold or issued.

As a Form 8-K, this filing reports that the company registered up to 920,000 common shares through a prospectus supplement; that creates registration capacity, not evidence of a completed sale or issuance.

The active shelf allows future registered offerings without a new registration each time, while a prospectus supplement sets the terms of a specific takedown; this filing does not establish those shares were sold or that proceeds were received.

The active shelf is dated July 31, 2026 and expires July 31, 2029; any later offering would be defined by its applicable prospectus supplement.

8-K Event Classification

2 items: 8.01, 9.01

2 items

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

Common stock registered: 920,000 shares Registration Statement number: 333-297857 Prospectus Supplement filing date: July 31, 2026 +1 more

4 metrics

Common stock registered 920,000 shares Maximum shares of common stock registered via Prospectus Supplement under Rule 424(b)(5)

Registration Statement number 333-297857 Shelf Registration Statement on Form S-3 referenced in the Prospectus Supplement

Prospectus Supplement filing date July 31, 2026 Date Interactive Brokers filed the Prospectus Supplement under Rule 424(b)(5)

Par value per common share $0.01 per share Par value of Interactive Brokers Group, Inc. common stock listed on Nasdaq Global Select Market

Key Terms

Prospectus Supplement, Rule 424(b)(5), Form S-3, Inline XBRL

4 terms

Prospectus Supplement regulatory

"filed a Prospectus Supplement under Rule 424(b)(5)"

A prospectus supplement is an additional document provided alongside a company's main offering details, offering updated or extra information about a specific financial product being sold. It helps investors understand the latest terms, risks, and details of the investment, similar to how an update or revision clarifies or expands on original instructions, ensuring they have current and complete information before making a decision.

Rule 424(b)(5) regulatory

"Prospectus Supplement under Rule 424(b)(5) to register"

Form S-3 regulatory

"from its shelf Registration Statement on Form S-3"

Form S-3 is a legal document companies use to register their stock sales with the government, making it easier and faster for them to raise money by selling shares to investors. It’s like having a pre-approved shopping list that lets a company quickly sell new shares when they need funds, without going through a lengthy approval process each time.

Inline XBRL technical

"tags are embedded within the Inline XBRL Document"

Inline XBRL is a file format for financial filings that embeds machine-readable data tags directly inside the human-readable report, so the same document can be read by people and parsed by software. For investors it makes extracting, comparing and verifying financial numbers faster and more reliable—like a grocery list where each item also has a barcode—reducing manual errors and speeding up analysis.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 07/31/2026 - 01:14 PM Accepted by SEC EDGAR 07/31/2026 - 01:14 PM Learn about SEC filing dates

FAQ

What event did Interactive Brokers Group (IBKR) disclose in this Form 8-K?

Interactive Brokers Group (IBKR) disclosed that it filed a Prospectus Supplement on July 31, 2026 under Rule 424(b)(5) to register up to 920,000 shares of its common stock under its shelf Form S-3 Registration Statement.

How many shares is Interactive Brokers Group (IBKR) registering in the new prospectus?

The company is registering up to 920,000 shares of its common stock. These shares are covered by a Prospectus Supplement filed under Rule 424(b)(5) and tied to the shelf Registration Statement on Form S-3, Registration No. 333-297857.

Under which SEC rule and form did Interactive Brokers (IBKR) file this share registration?

Interactive Brokers filed a Prospectus Supplement under Rule 424(b)(5) relating to a shelf Registration Statement on Form S-3. The Registration Statement is identified as No. 333-297857 and provides the framework for registering the 920,000 common shares.

What legal opinion is associated with Interactive Brokers’ (IBKR) 920,000-share registration?

A legal opinion from Dechert LLP addresses the validity of the registered common shares. This opinion is filed as Exhibit 5.3 and is incorporated by reference into the Form S-3 Registration Statement covering the 920,000 shares.

What additional exhibit did Interactive Brokers (IBKR) include with this disclosure?

Interactive Brokers included a Cover Page Interactive Data File as Exhibit 104. This exhibit contains the cover page XBRL tags embedded within the Inline XBRL document, supporting structured electronic reporting of the filing’s key cover-page information.

0001381197false00013811972026-07-312026-07-31

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 31, 2026

Interactive Brokers Group, Inc.

(Exact name of Registrant as Specified in Its Charter)

Delaware			001-33440	30-0390693
(State or Other Jurisdiction of Incorporation)			(Commission File Number)	(IRS Employer Identification No.)
ONE PICKWICK PLAZA
GREENWICH, Connecticut				06830
(Address of Principal Executive Offices)				(Zip Code)

Registrant’s Telephone Number, Including Area Code: 203 618-5800

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

☐Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of each class		Trading Symbol(s)		Name of each exchange on which registered
Common Stock, par value $.01 per share		IBKR		The Nasdaq Global Select Market

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 8.01 Other Events.

On July 31, 2026, Interactive Brokers Group, Inc. (the "Company") filed a Prospectus Supplement under Rule 424(b)(5) to register up to 920,000 shares of the Company's common stock from its shelf Registration Statement on Form S-3 (Registration Statement No. 333-297857) (the "Registration Statement") filed with the SEC on July 31, 2026. The legal opinion letter of Dechert LLP, counsel to the Company, regarding the validity of the shares is filed as Exhibit 5.3 to this Current Report on Form 8-K. The legal opinion letter is also hereby incorporated by reference into the Registration Statement, as Exhibit 5.3 thereto.

Item 9.01 Financial Statements and Exhibits.

Exhibit No.		Description
5.3		Opinion of Dechert
104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL Document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Date:	July 31, 2026	By:	/s/ Paul J. Brody
			Paul J Brody Chief Financial Officer, Treasurer and Secretary

Filing Exhibits & Attachments

2 documents

Other Documents

• EX-5.3 EX-5.3 10.9 KB
• EX-101 XBRL TAXONOMY EXTENSION SCHEMA WITH EMBEDDED LINKBASES DOCUMENT 23.4 KB