SCHEDULE 13D/A

X4 Pharmaceuticals Inc

Common Stock, par value $0.001 per share · CUSIP: 98420X202

Event date: 2025-10-27

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

• Growth Equity Opportunities 18 VGE, LLCReported CIK 0001917895

  Shares: 5,057,610.00 · Class: 6.2%

• NEA 18 Venture Growth Equity, L.P.Reported CIK 0001880239

  Shares: 5,057,610.00 · Class: 6.2%

• NEA Partners 18 VGE, L.P.Reported CIK 0001898446

  Shares: 5,057,610.00 · Class: 6.2%

• NEA 18 VGE GP, LLCReported CIK 0001898598

  Shares: 5,057,610.00 · Class: 6.2%

• Ali BehbahaniReported CIK 0001613867

  Shares: 5,057,610.00 · Class: 6.2%

• Carmen ChangReported CIK 0001746342

  Shares: 5,057,610.00 · Class: 6.2%

• Anthony A. Florence, Jr.Reported CIK 0001559827

  Shares: 5,057,610.00 · Class: 6.2%

• Mohamad H. MakhzoumiReported CIK 0001630226

  Shares: 5,057,610.00 · Class: 6.2%

• Edward T. MathersReported CIK 0001328625

  Shares: 5,057,610.00 · Class: 6.2%

• Scott D. SandellReported CIK 0001237289

  Shares: 5,057,610.00 · Class: 6.2%

• Paul WalkerReported CIK 0001553150

  Shares: 5,057,610.00 · Class: 6.2%

• Rick YangReported CIK 0001851328

  Shares: 5,057,610.00 · Class: 6.2%

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