SCHEDULE 13G

PEPGEN INC

Common Stock, par value $0.0001 per share · CUSIP: 713317105

Event date: 2025-09-26

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

• VIKING GLOBAL INVESTORS LP

  Shares: 3,482,434 · Class: 5.1%

• Viking Global Opportunities Parent GP LLC

  Shares: 3,482,434 · Class: 5.1%

• Viking Global Opportunities GP LLC

  Shares: 3,482,434 · Class: 5.1%

• Viking Global Opportunities Portfolio GP LLC

  Shares: 3,482,434 · Class: 5.1%

• Viking Global Opportunities Illiquid Investments Sub-Master LP

  Shares: 3,482,434 · Class: 5.1%

• HALVORSEN OLE ANDREAS

  Shares: 3,482,434 · Class: 5.1%

• Ott David C.

  Shares: 3,482,434 · Class: 5.1%

• Shabet Rose Sharon

  Shares: 3,482,434 · Class: 5.1%

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