Nektar Therapeutics (NKTR) had the highest return in June 2025 by a mid-cap US stock, returning 132.8%.

ASSET	MONTH	% RETURN
Nektar Therapeutics (NKTR)	June 2025	132.82%
Tango Therapeutics (TNGX)	June 2025	127.56%
Plug Power (PLUG)	June 2025	75.11%
Almonty Industries Inc Common Shares (ALM)	June 2025	70.09%
Quantum Computing (QUBT)	June 2025	69.5%
QuantumScape Corporation Class A Common Stock (QS)	June 2025	68.84%
ViaSat (VSAT)	June 2025	67.82%
Sezzle (SEZL)	June 2025	66.74%
Ascentage Pharma Group International (AAPG)	June 2025	60.06%
AeroVironment (AVAV)	June 2025	55.71%
Amprius Technologies (AMPX)	June 2025	55.35%
Cipher Mining (CIFR)	June 2025	55.19%
Oscar Health (OSCR)	June 2025	53.69%
Telesat (TSAT)	June 2025	52.56%
Bausch Health Companies (BHC)	June 2025	47.35%
Centrus Energy (LEU)	June 2025	46.5%
TMC the metals (TMC)	June 2025	44.9%
Bel Fuse A (BELFA)	June 2025	43.1%
Fluence Energy (FLNC)	June 2025	43.07%
Ondas (ONDS)	June 2025	42.22%
Riot Blockchain (RIOT)	June 2025	41.25%
Avis Budget (CAR)	June 2025	38%
CommScope (VISN)	June 2025	38%
Taseko Mines (TGB)	June 2025	37.55%
AXT (AXTI)	June 2025	37.5%

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