Regencell Bioscience (RGC) had the highest return in May 2025 by a mid-cap US stock, returning 1,494.3%.

ASSET	MONTH	% RETURN
Regencell Bioscience (RGC)	May 2025	1,494.29%
Strive (ASST)	May 2025	1,082.52%
Navitas Semiconductor (NVTS)	May 2025	162.89%
D-Wave Quantum Inc Common Stock (QBTS)	May 2025	132.95%
Oklo (OKLO)	May 2025	113.01%
Dave (DAVE)	May 2025	107.52%
Pony AI Inc American Depositary Shares (PONY)	May 2025	105.88%
Sezzle (SEZL)	May 2025	99.46%
nLIGHT (LASR)	May 2025	93.97%
Nuscale Power (SMR)	May 2025	85.13%
ELF Beauty (ELF)	May 2025	80.85%
Centrus Energy (LEU)	May 2025	79.06%
Tutor Perini (TPC)	May 2025	68.48%
Hims Hers Health (HIMS)	May 2025	67.73%
Tango Therapeutics (TNGX)	May 2025	66.92%
Ouster, Inc Common Stock (OUST)	May 2025	59.24%
Ondas (ONDS)	May 2025	56.41%
ATAI Life Sciences (ATAI)	May 2025	55.03%
Boot Barn (BOOT)	May 2025	52.44%
Par Pacific (PARR)	May 2025	49.93%
Delek US Energy (DK)	May 2025	49.08%
ACADIA Pharmaceuticals (ACAD)	May 2025	47.44%
Life360, Inc Common Stock (LIF)	May 2025	46.09%
Applied Digital (APLD)	May 2025	45.94%
Advance Auto Parts (AAP)	May 2025	45.64%

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