Definium Therapeutics (DFTX) had the highest return last month by a mid-cap US stock, returning 95.5%.

ASSET	MONTH	% RETURN
Definium Therapeutics (DFTX)	June 2026	95.51%
Newell Brands (NWL)	June 2026	80.06%
MBX Biosciences, Inc Common Stock (MBX)	June 2026	76.08%
Ultra Clean (UCTT)	June 2026	71.96%
Oruka Therapeutics (ORKA)	June 2026	65.43%
Uniqure (QURE)	June 2026	64.97%
Ichor (ICHR)	June 2026	61.72%
Victoria's Secret (VSXY)	June 2026	59.74%
Alignment Healthcare LLC (ALHC)	June 2026	56.03%
Twist Bioscience (TWST)	June 2026	53.85%
Acm Research (ACMR)	June 2026	51.96%
Enova International (ENVA)	June 2026	50.34%
Compass (COMP)	June 2026	50.18%
Allegro Microsystems (ALGM)	June 2026	47.42%
TG Therapeutics (TGTX)	June 2026	46.31%
Sezzle (SEZL)	June 2026	46.18%
Hinge Health (HNGE)	June 2026	44.73%
Tango Therapeutics (TNGX)	June 2026	43.66%
Adaptive Biotechnologies (ADPT)	June 2026	43.1%
Fortune Brands Innovations (FBIN)	June 2026	43.04%
Kymera Therapeutics (KYMR)	June 2026	42.16%
Ultragenyx (RARE)	June 2026	40.47%
Ouster, Inc Common Stock (OUST)	June 2026	38.96%
Lifestance Health (LFST)	June 2026	38.73%
MaxLinear (MXL)	June 2026	38.73%

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