Twenty One Capital (XXI) had the highest return in April 2025 by a mid-cap US stock, returning 302%.

ASSET	MONTH	% RETURN
Twenty One Capital (XXI)	April 2025	302%
Regencell Bioscience (RGC)	April 2025	83.98%
TMC the metals (TMC)	April 2025	75.42%
USA Rare Earth (USAR)	April 2025	72.01%
Structure Therapeutics Inc American Depositary Shares (GPCR)	April 2025	58.73%
Kodiak Sciences (KOD)	April 2025	56.27%
Sezzle (SEZL)	April 2025	53.15%
Stoke Therapeutics (STOK)	April 2025	48.1%
Amylyx Pharmaceuticals (AMLX)	April 2025	45.58%
Sellas Life Sciences (SLS)	April 2025	43.52%
MBX Biosciences, Inc Common Stock (MBX)	April 2025	43.5%
NovaGold Resources (NG)	April 2025	41.95%
Perpetua Resources (PPTA)	April 2025	39.75%
TransMedics (TMDX)	April 2025	38.72%
Uniqure (QURE)	April 2025	37.05%
GRAIL, LLC (GRAL)	April 2025	36.4%
Maase (MAAS)	April 2025	36.31%
Loar (LOAR)	April 2025	35.19%
StoneCo (STNE)	April 2025	34.16%
Pegasystems (PEGA)	April 2025	32.51%
Immunome (IMNM)	April 2025	32.18%
PagSeguro Digital (PAGS)	April 2025	31.11%
Redwire (RDW)	April 2025	29.88%
Relay Therapeutics (RLAY)	April 2025	29.07%
Nuvation Bio (NUVB)	April 2025	27.84%

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