# EDGAR Filing Document

**Accession Number:** 0001972305
**File Stem:** 0001213900-26-030811
**Filing Date:** 2026-3
**Character Count:** 8447
**Document Hash:** 3b81ded3ffc238c280ffd7b264ad752b
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001213900-26-030811.hdr.sgml**: 20260318

**ACCESSION NUMBER**: 0001213900-26-030811

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260316

**FILED AS OF DATE**: 20260318

**DATE AS OF CHANGE**: 20260318

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Nelson Daniel D
- **CENTRAL INDEX KEY:** 0001972305

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-43194
- **FILM NUMBER:** 26769826

**MAIL ADDRESS:**
- **STREET 1:** 8355 EAST HARTFORD ROAD
- **STREET 2:** SUITE 100
- **CITY:** SCOTTSDALE
- **STATE:** AZ
- **ZIP:** 85260
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** BlockchAIn Digital Infrastructure, Inc.
- **CENTRAL INDEX KEY:** 0002070542
- **STANDARD INDUSTRIAL CLASSIFICATION:** [6221]
- **ORGANIZATION NAME:** 09 Crypto Assets
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 1540 BROADWAY, SUITE 1010
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10036
- **BUSINESS PHONE:** 917-558-3563

**MAIL ADDRESS:**
- **STREET 1:** 1540 BROADWAY, SUITE 1010
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10036

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Nelson Daniel D<br><sub>(Last) (First) (Middle)</sub><br>1540 BROADWAY, STE 1010<br><sub>(Street)</sub><br>NEW YORK, NY 10036<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-03-16 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [ ] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>BlockchAIn Digital Infrastructure, Inc. [ AIB ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2026-03-16 |  | A |  | 37527 | A | <sup>(1)</sup> | 37527 | D |  |
| Common Stock | 2026-03-16 |  | A |  | 2917 | A | <sup>(1)</sup> | 2917 | I | By The Nelson Revocable Living Trust<sup>(2)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Stock Option (right to buy) | $1594.17 | 2026-03-16 |  | A |  | 59 |  | 2026-03-16 | 2032-09-28 | Common Stock | 59 | <sup>(3)</sup> | 59 | D |  |
| Stock Option (right to buy) | $1594.17 | 2026-03-16 |  | A |  | 10 |  | 2026-03-16 | 2032-09-28 | Common Stock | 10 | <sup>(4)</sup> | 10 | D |  |
| Stock Option (right to buy) | $1157.06 | 2026-03-16 |  | A |  | 195 |  | 2026-03-16 | 2033-11-21 | Common Stock | 195 | <sup>(5)</sup> | 195 | D |  |

---

### Footnotes:

(1) Pursuant to the Business Combination Agreement, dated as of May 27, 2025, by and among Signing Day Sports, Inc., a Delaware corporation ("SGN"), One Blockchain LLC, a Delaware limited liability company, BlockchAIn Digital Infrastructure, Inc., a Delaware corporation ("BlockchAIn"), BCDI Merger Sub I Inc., a Delaware corporation, and BCDI Merger Sub II LLC, a Delaware limited liability company, as amended (the "Business Combination Agreement"), on the date of the closing (the "Closing") of the transactions contemplated by the Business Combination Agreement, or March 16, 2026, the reporting person received 0.09334 common shares of BlockchAIn for every share of common stock of SGN held by the reporting person, subject to rounding adjustments. The last reported sale price of SGN common stock after the Closing was $0.54 per share, as reported on March 16, 2026. The first reported sale price after the Closing of BlockchAIn's common stock was $4.60 per share, as reported on March 17, 2026.

(2) The reporting person is a co-trustee of The Nelson Revocable Living Trust, an Arizona trust provided for by the Nelson Revocable Living Trust Agreement established on March 9, 1999 and amended and restated on November 21, 2005. The reporting person disclaims beneficial ownership of these securities except to the extent of his pecuniary interest therein.

(3) Pursuant to the terms of the Business Combination Agreement, on the date of the Closing, the reporting person's employee stock option to acquire 625 shares of SGN common stock for $148.80 per share was assumed by BlockchAIn and automatically converted into an option to purchase 59 common shares of BlockchAIn exercisable for $1,594.17 per share.

(4) Pursuant to the terms of the Business Combination Agreement, on the date of the Closing, the reporting person's employee stock option to acquire 105 shares of SGN common stock for $148.80 per share was assumed by BlockchAIn and automatically converted into an option to purchase 10 common shares of BlockchAIn exercisable for $1,594.17 per share.

(5) Pursuant to the terms of the Business Combination Agreement, on the date of the Closing, the reporting person's employee stock option to acquire 2,084 shares of SGN common stock for $108.00 per share was assumed by BlockchAIn and automatically converted into an option to purchase 195 common shares of BlockchAIn exercisable for $1,157.06 per share.

**Signature:** /s/ Daniel D. Nelson  
**Date:** 2026-03-18

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**