Mstone Partners Healthcare Ltd - 29 Jan 2026 SCHEDULE 13D Report for Polaryx Therapeutics, Inc. Common stock, par value $0.0001 per share ("Common Stock")

Filing Manager
Mstone Partners Healthcare Ltd
Reporting Manager
Alex Keun Mo Yang
Security
Polaryx Therapeutics, Inc. Common stock, par value $0.0001 per share ("Common Stock")
Shares outstanding
47,384,992 shares
Disclosed Ownership
22,744,796 shares
Ownership
48%
Form type
SCHEDULE 13D
Filing time
05 Feb 2026, 16:05:20 UTC
Date of event
29 Jan 2026
SEC
View on sec.gov

Reporting Managers (4)

Name Ownership Shares Owned sole voting power shared voting power Signature Title CIK
Mstone Partners Healthcare Limited 47% 22,452,954 0 22,452,954 /s/ Alex Keun Mo Yang Chief Executive Officer 0002104809
MBstone Biotech Flagship Limited 0.4% 183,560 0 183,560 /s/ Alex Keun Mo Yang Chief Executive Officer
Mstone Pediaorphan Singapore I Pte. Limited 0.2% 108,282 0 108,282 /s/ Alex Keun Mo Yang Chief Executive Officer
Alex Keun Mo Yang 48% 22,744,796 0 22,744,796 /s/ Alex Keun Mo Yang Reporting person 0002103399