QMMM Holdings Limited Ordinary Shares (QMMM) had the highest return in September 2025 by a mid-cap US stock, returning 2,361.9%.

ASSET	MONTH	% RETURN
QMMM Holdings Limited Ordinary Shares (QMMM)	September 2025	2,361.86%
Uniqure (QURE)	September 2025	258.54%
Bitfarms (KEEL)	September 2025	115.27%
Innodata (INOD)	September 2025	110%
BitVentures (BVC)	September 2025	103.65%
Nektar Therapeutics (NKTR)	September 2025	96.14%
Planet Labs PBC (PL)	September 2025	92.01%
Opendoor Technologies (OPEN)	September 2025	88.86%
Rigetti Computing (RGTI)	September 2025	88.13%
GRAIL, LLC (GRAL)	September 2025	86.59%
Kodiak Sciences (KOD)	September 2025	84.97%
Cipher Mining (CIFR)	September 2025	69.65%
Dianthus Therapeutics (DNTH)	September 2025	68.23%
Rapport Therapeutics, Inc Common Stock (RAPP)	September 2025	67.8%
Mineralys Therapeutics, Inc Common Stock (MLYS)	September 2025	67.49%
D-Wave Quantum Inc Common Stock (QBTS)	September 2025	63.05%
Centrus Energy (LEU)	September 2025	61.1%
Pony AI Inc American Depositary Shares (PONY)	September 2025	60.64%
Oklo (OKLO)	September 2025	59.12%
AXT (AXTI)	September 2025	58.66%
CleanSpark (CLSK)	September 2025	56.42%
Septerna, Inc Common Stock (SEPN)	September 2025	55.71%
Plug Power (PLUG)	September 2025	54.3%
Peabody Energy (BTU)	September 2025	54.01%
Fluence Energy (FLNC)	September 2025	52.97%

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