Xanadu Quantum Technologies Limited Class B Subordinate Voting Shares (XNDU) had the lowest return in May 2026 by a mid-cap US stock, returning -45.2%.

ASSET	MONTH	% RETURN
Xanadu Quantum Technologies Limited Class B Subordinate Voting Shares (XNDU)	May 2026	-45.19%
Octave Intelligence (OCTV)	May 2026	-38.57%
Octave Intelligence plc Class B Ordinary Shares When Issued (OCTVV)	May 2026	-38.57%
Shake Shack (SHAK)	May 2026	-37.7%
TransMedics (TMDX)	May 2026	-33.45%
Primoris Services (PRIM)	May 2026	-30.76%
Evolution Metals & Technologies Corp Common Stock (EMAT)	May 2026	-29.32%
Glaukos (GKOS)	May 2026	-28%
Installed Building Products (IBP)	May 2026	-27.55%
Alignment Healthcare LLC (ALHC)	May 2026	-27.46%
Wix (WIX)	May 2026	-27.25%
Cosan SA ADR (CSAN)	May 2026	-26.29%
NIQ Global Intelligence (NIQ)	May 2026	-24.93%
OSI Systems (OSIS)	May 2026	-24.69%
Klaviyo (KVYO)	May 2026	-24.57%
Westlake Chemical (WLK)	May 2026	-24.53%
Resideo Technologies (REZI)	May 2026	-24.27%
Nektar Therapeutics (NKTR)	May 2026	-23.95%
Comstock Resources (CRK)	May 2026	-23.92%
Bright Horizons Family Solutions (BFAM)	May 2026	-23.65%
Freshpet (FRPT)	May 2026	-23.42%
Tutor Perini (TPC)	May 2026	-22.9%
Whirlpool (WHR)	May 2026	-22.53%
Celanese (CE)	May 2026	-22.4%
ADMA Biologics (ADMA)	May 2026	-22.37%

Mid-cap stocks are treated as having a market cap between $2B and $10B.