Marathon Digital (MARA) had the highest return last year by a mid-cap US stock, returning 556.1%.

ASSET	YEAR	% RETURN
Marathon Digital (MARA)	2023	556.15%
QXO (QXO)	2023	525.37%
MoonLake Immunotherapeutics (MLTX)	2023	469.72%
CleanSpark (CLSK)	2023	425.24%
BridgeBio Pharma (BBIO)	2023	418.89%
Riot Blockchain (RIOT)	2023	343.27%
Dream Finders Homes (DFH)	2023	301.47%
Abercrombie & Fitch (ANF)	2023	279.6%
Oscar Health (OSCR)	2023	266%
Aurora Innovation (AUR)	2023	244.09%
Camtek (CAMT)	2023	211.96%
SkyWest (SKYW)	2023	210.9%
Biohaven Pharmaceutical (BHVN)	2023	204.63%
Upstart Holdings (UPST)	2023	200.88%
Modine Manufacturing (MOD)	2023	196.57%
Amneal Pharmaceuticals, Inc Class A Common Stock (AMRX)	2023	196.1%
M/I Homes (MHO)	2023	193.06%
Structure Therapeutics Inc American Depositary Shares (GPCR)	2023	171.73%
Sterling Construction (STRL)	2023	165.25%
Celestica (CLS)	2023	158.66%
ELF Beauty (ELF)	2023	156.97%
Powell Industries (POWL)	2023	155.62%
Arlington Asset Investment (AI)	2023	151.18%
Inter & Co Inc Class A Common Shares (INTR)	2023	150.45%
Centessa Pharmaceuticals PLC ADR (CNTA)	2023	147.2%

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