Rigetti Computing (RGTI) had the highest return on May 21 by a mid-cap US stock, returning 18%.

ASSET	DATE	% RETURN
Rigetti Computing (RGTI)	5/21/2026	17.96%
Enphase Energy (ENPH)	5/21/2026	17.91%
AXT (AXTI)	5/21/2026	15.83%
Abcellera Biologics (ABCL)	5/21/2026	13.72%
Applied Digital (APLD)	5/21/2026	13.33%
SolarEdge Technologies (SEDG)	5/21/2026	12.34%
Twist Bioscience (TWST)	5/21/2026	11.84%
Ouster, Inc Common Stock (OUST)	5/21/2026	11.08%
Rumble (RUM)	5/21/2026	10.87%
Nuscale Power (SMR)	5/21/2026	9.79%
Fervo Energy Company Class A common stock (FRVO)	5/21/2026	9.59%
Boot Barn (BOOT)	5/21/2026	9.56%
Strive (ASST)	5/21/2026	9.13%
Banco Macro SA B ADR (BMA)	5/21/2026	9.05%
Beta Technologies (BETA)	5/21/2026	9.01%
Garrett Motion (GTX)	5/21/2026	8.92%
Definium Therapeutics (DFTX)	5/21/2026	8.89%
Alamar Biosciences, Inc Common Stock (ALMR)	5/21/2026	8.86%
Immunome (IMNM)	5/21/2026	8.71%
Hut 8 Corp Common Stock (HUT)	5/21/2026	8.66%
BBVA Banco Frances SA ADR (BBAR)	5/21/2026	8.62%
Cipher Mining (CIFR)	5/21/2026	8.58%
Navitas Semiconductor (NVTS)	5/21/2026	8.52%
Biohaven (BHVN)	5/21/2026	8.47%
Nurix Therapeutics (NRIX)	5/21/2026	8.21%

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