SCHEDULE 13G/A

HAWAIIAN ELECTRIC CO INC

Common Stock, no par value per share · CUSIP: 419870100

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: 3,825,214 · Class: 2.2%

• Zimmer Financial Services Group LLC

  Shares: 3,825,214 · Class: 2.2%

• Zimmer Partners GP, LLC

  Shares: 3,825,214 · Class: 2.2%

• Stuart J. Zimmer

  Shares: 3,825,214 · Class: 2.2%

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