QXO (QXO) had the highest return in December 2023 by a mid-cap US stock, returning 364.9%.

ASSET	MONTH	% RETURN
QXO (QXO)	December 2023	364.95%
Cytokinetics (CYTK)	December 2023	149%
Sezzle Inc Common Stock (SEZL)	December 2023	105.41%
Terawulf (WULF)	December 2023	101.68%
Marathon Digital (MARA)	December 2023	92.54%
CleanSpark (CLSK)	December 2023	86.63%
Edgewise Therapeutics (EWTX)	December 2023	81.73%
Compass (COMP)	December 2023	71.69%
Longboard Pharmaceuticals (LBPH)	December 2023	60.37%
Compania de Minas Buenaventura SAA ADR (BVN)	December 2023	60.25%
GeneDx (WGS)	December 2023	59.88%
EchoStar (SATS)	December 2023	56.17%
Twist Bioscience (TWST)	December 2023	54.74%
Upstart Holdings (UPST)	December 2023	54.31%
Sunrun (RUN)	December 2023	54.08%
Century Aluminum (CENX)	December 2023	53.28%
Viking Therapeutics (VKTX)	December 2023	50.08%
Scholar Rock (SRRK)	December 2023	49.44%
Tandem Diabetes Care (TNDM)	December 2023	48.42%
Cipher Mining (CIFR)	December 2023	47.5%
Verona Pharma PLC ADR (VRNA)	December 2023	47.26%
Dream Finders Homes (DFH)	December 2023	45.97%
Recursion Pharmaceuticals (RXRX)	December 2023	45.86%
Applied Blockchain (APLD)	December 2023	44.95%
Apogee Therapeutics, Inc Common Stock (APGE)	December 2023	44.69%

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