Douglas M. Schafer Jr. - 13 Aug 2025 Form 3 Insider Report for MIAMI INTERNATIONAL HOLDINGS, INC. (MIAX)

Role
EVP and CIO
Signature
/s/Alessandra Maria Corona Henriques, Attorney-in-Fact
Issuer symbol
MIAX
Transactions as of
13 Aug 2025
Net transactions value
$0
Form type
3
Filing time
13 Aug 2025, 17:07:56 UTC
Next filing
19 Aug 2025
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Schafer Douglas M. JR EVP and CIO C/O MIAMI INTERNATIONAL HOLDINGS, INC., 7 ROSZEL ROAD, SUITE 1A, PRINCETON /s/Alessandra Maria Corona Henriques, Attorney-in-Fact 13 Aug 2025 0002079445

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
holding MIAX Common Stock 150,000 13 Aug 2025 Direct

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
holding MIAX Series B Preferred Stock 13 Aug 2025 Common Stock 500 Direct F1
holding MIAX Nonvoting Common Stock 13 Aug 2025 Common Stock 409,006 Direct F2
holding MIAX Incentive Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 16,666 $12.00 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 19,710 $15.22 Direct F3
holding MIAX Incentive Stock Option (Right to Buy) 13 Aug 2025 Common Stock 10,080 $19.84 Direct F4
holding MIAX Incentive Stock Option (Right to Buy) 13 Aug 2025 Common Stock 9 $22.40 Direct F5
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 150,000 $12.00 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 133,334 $12.00 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 200,000 $12.00 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 130,290 $15.22 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Nonvoting Common Stock 150,000 $16.14 Direct F6
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Common Stock 114,920 $19.84 Direct F7
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Common Stock 100,000 $20.08 Direct F8
holding MIAX Nonqualified Stock Option (Right to Buy) 13 Aug 2025 Common Stock 66,072 $22.40 Direct F9
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 The shares of Series B Preferred Stock are convertible on a one-for-one basis into shares of common stock commencing on the Company's initial public offering of its common stock ("IPO") effective date, which is August 13, 2025 and are held jointly with his spouse with right of survivorship. The Series B Preferred Stock has no expiration date.
F2 The shares of nonvoting common stock are convertible on a one-for-one basis into shares of common stock commencing at any time. The nonvoting common stock has no expiration date.
F3 The incentive stock options are fully vested. The options were granted initially as the right to buy nonvoting common stock. On the closing date of the IPO, these will convert to the right to buy common stock instead of nonvoting common stock.
F4 5,040 of the shares subject to this incentive stock option are vested and the remaining 5,040 will vest on March 29, 2026, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F5 4,464 of the shares subject to this incentive stock option will vest on June 17, 2026 and the remaining 4,464 will vest on June 17, 2028 subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F6 The nonqualified stock options are fully vested. The options were granted initially as the right to buy nonvoting common stock. On the closing date of the IPO, these will convert to the right to buy common stock instead of nonvoting common stock.
F7 78,294 of the shares subject to this nonqualified stock option are vested and the remaining 36,626 will vest on March 29, 2026 subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F8 50,000 of the shares subject to this nonqualified stock option are vested and the remaining 50,000 will vest on December 31, 2025, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.
F9 25,000 of the shares subject to this nonqualified stock option will vest on June 16, 2026, 20,536 will vest on June 16, 2027 and the remaining 20,536, will vest on June 16, 2028, subject to the reporting person's continued service to the Issuer or its subsidiaries through the applicable vesting date.

Remarks:

See Exhibit 24.1 - Power of Attorney