13D Filing: Southport Sponsor Reports 27.7% of New SPAC

The news

Southport Acquisition Sponsor II LLC, its managing member Southport Sponsor Management II, LLC and Jeb Spencer filed a Schedule 13D on Oct. 7, 2026 for Southport Acquisition Corp. II (PORT), a newly public blank-check company based in Greenwich, Connecticut. The three reporting persons beneficially own 8,166,667 ordinary shares, or 27.7% of the class. That is 7,666,667 Class B founder shares plus 500,000 Class A shares that were part of private placement units. The percentage rests on 29,436,667 ordinary shares outstanding at Oct. 2, 2026: 21,770,000 Class A and 7,666,667 Class B, as the company reported in an 8-K filed Oct. 5. The event date on the cover is Sept. 30, 2026.

Spencer is the company’s chairman, chief executive and chief financial officer and controls the sponsor through the management entity. Spencer and the management entity each disclaim beneficial ownership beyond any pecuniary interest they may have.

Our analysis

A SPAC sponsor’s 13D is mostly a statement of economics, and this one lays them out. The sponsor paid $25,000, about $0.003 per share, in July 2026 for the 7,666,667 founder shares under a subscription agreement dated July 15. On Oct. 2, as the initial public offering closed, it bought 500,000 placement units at $10.00 each. Together those payments produce the $5,025,000 aggregate purchase price the filing reports, drawn from the sponsor’s working capital. Each placement unit holds one Class A share and one-half of a warrant; each whole warrant is exercisable for one Class A share at $11.50 starting 30 days after an initial business combination.

The filing then describes the strings attached. Under the insider letter signed Sept. 30, the sponsor and the company’s officers and directors agreed to vote their founder shares, placement shares and any public shares in favor of a proposed business combination, with a narrow carve-out for Class A shares bought after the company announces a deal. The sponsor also agreed not to redeem shares in a deal vote, and not to propose charter amendments that would change the obligation to redeem 100% of public shares if no business combination closes within 24 months of the offering unless public holders get a redemption opportunity. The placement units are locked up until 30 days after a business combination.

Read together, the terms show how a sponsor’s 27.7% differs from an operating-company stake. The founder shares cost a fraction of a cent and are covered by a no-redemption commitment, while the placement units carry real capital at risk. The filing’s Item 4 says the shares were acquired for investment purposes, and the only transaction it describes is the company’s intended business combination.

A sponsor’s 27.7% is a promote and a vote commitment, not an activist position.

Room for disagreement

The 27.7% figure invites comparison with activist stakes, but the denominators differ. It counts founder shares alongside the public float, and the founder shares convert one-for-one at the time of a business combination, which may change both the numerator and the denominator. Some readers would also argue that a 13D from the sponsor of a SPAC that has not yet identified a target is too early to tell them anything.

The counterpoint is that the first 13D fixes the baseline. Later amendments, particularly any filed when a merger agreement is signed, will be read against these numbers, including the vote commitments and lock-up.

What to watch

• An 8-K announcing a business combination agreement, which is the event that would trigger a Schedule 13D amendment and the first test of the voting commitments.
• Disclosure of the trust account and any extension terms in the company’s periodic reports.
• Whether the sponsor adds to its position, which would also require an amendment.