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%
Sandisk (SNDK)	September 2025	119.96%
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%
Olema Pharmaceuticals (OLMA)	September 2025	78.65%
Maze Therapeutics, Inc Common Stock (MAZE)	September 2025	77.12%
Eos Energy Enterprises (EOSE)	September 2025	69.75%
Cipher Mining (CIFR)	September 2025	69.65%
Mineralys Therapeutics, Inc Common Stock (MLYS)	September 2025	67.49%
D-Wave Quantum (QBTS)	September 2025	63.05%
Centrus Energy (LEU)	September 2025	61.1%
Pony AI Inc American Depositary Shares (PONY)	September 2025	60.64%
Quantumscape (QS)	September 2025	58.56%
CleanSpark (CLSK)	September 2025	56.42%
Plug Power (PLUG)	September 2025	54.3%
Peabody Energy (BTU)	September 2025	54.01%
Fluence Energy (FLNC)	September 2025	52.97%
Arrowhead Pharmaceuticals (ARWR)	September 2025	51.74%
Applied Digital (APLD)	September 2025	51.62%
CG Oncology, Inc Common stock (CGON)	September 2025	50.64%
Metsera, Inc Common Stock (MTSR)	September 2025	50.63%
Beam Therapeutics (BEAM)	September 2025	49.91%
Cidara Therapeutics (CDTX)	September 2025	46.89%

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