SCHEDULE 13G/A

Sun Country Airlines Holdings Inc

Common Stock, par value $0.01 per share · CUSIP: 866683105

Event date: 2025-06-30

Reporting persons may disclose overlapping interests. Their amounts are shown individually and are not added into a filing total.

Filing-level shares

Unavailable

Percent of class

Unavailable

• Zimmer Partners, LP

  Shares: 2,225,900 · Class: 4.2%

• Zimmer Financial Services Group LLC

  Shares: 2,225,900 · Class: 4.2%

• Zimmer Partners GP, LLC

  Shares: 2,225,900 · Class: 4.2%

• Stuart J. Zimmer

  Shares: 2,225,900 · Class: 4.2%

Amounts are as disclosed in this filing. Schedule type alone does not establish investment intent.