Madrigal Pharmaceuticals (MDGL) had the highest return in December 2022 by a mid-cap US stock, returning 311%.

ASSET	MONTH	% RETURN
Madrigal Pharmaceuticals (MDGL)	December 2022	311%
Viking Therapeutics (VKTX)	December 2022	131.53%
Verona Pharma PLC ADR (VRNA)	December 2022	101.62%
Avidity Biosciences (RNA)	December 2022	90.47%
Soleno Therapeutics (SLNO)	December 2022	59.68%
Arcellx (ACLX)	December 2022	55.44%
Alvotech (ALVO)	December 2022	53.85%
Bilibili (BILI)	December 2022	42.2%
Roivant Sciences (ROIV)	December 2022	38.96%
GDS (GDS)	December 2022	38.86%
Protagonist Therapeutics (PTGX)	December 2022	37.75%
Melco Resorts & Entertainment (MLCO)	December 2022	37.23%
SoundHound AI (SOUN)	December 2022	37.21%
NewAmsterdam Pharma Company NV Ordinary Shares (NAMS)	December 2022	37.11%
Immunovant (IMVT)	December 2022	35.29%
Global Business Travel (GBTG)	December 2022	35%
TG Therapeutics (TGTX)	December 2022	33.22%
Powell Industries (POWL)	December 2022	32.8%
360 DigiTech (QFIN)	December 2022	30.87%
Kingsoft Cloud Holdings (KC)	December 2022	28.09%
Vipshop (VIPS)	December 2022	27.6%
Ultragenyx (RARE)	December 2022	26.69%
Embotelladora Andina (AKO.B)	December 2022	26.06%
New Oriental Education & Technology (EDU)	December 2022	25.84%
Arrowhead Pharmaceuticals (ARWR)	December 2022	25.53%

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