WM Technology (MAPSW) had the best day in December 2022 by a mid-cap US stock on December 9, 2022, returning 87.9%.

ASSET	DATE	% RETURN
WM Technology (MAPSW)	12/9/2022	87.93%
SoundHound AI (SOUN)	12/30/2022	75.25%
Soleno Therapeutics (SLNO)	12/19/2022	66.67%
Advantage Solutions (ADVWW)	12/23/2022	35.75%
Viking Therapeutics (VKTX)	12/19/2022	28.26%
Sharplink Gaming (SBET)	12/21/2022	28%
Terawulf (WULF)	12/23/2022	26.23%
Soleno Therapeutics (SLNO)	12/27/2022	26.17%
Verona Pharma PLC ADR (VRNA)	12/21/2022	24.52%
Cipher Mining (CIFR)	12/30/2022	24.44%
Advantage Solutions (ADVWW)	12/9/2022	24.13%
NewAmsterdam Pharma Company NV Ordinary Shares (NAMS)	12/15/2022	23.84%
Celcuity LLC (CELC)	12/8/2022	23.1%
Advantage Solutions (ADVWW)	12/19/2022	21.43%
Terawulf (WULF)	12/12/2022	21.21%
Terawulf (WULF)	12/8/2022	21.18%
Pagaya Technologies (PGY)	12/27/2022	20.81%
Celcuity LLC (CELC)	12/19/2022	20.24%
Sharplink Gaming (SBET)	12/15/2022	20%
TAL Education (TAL)	12/20/2022	19.61%
IREN (IREN)	12/30/2022	19.05%
Rhythm Pharmaceuticals (RYTM)	12/12/2022	18.7%
WM Technology (MAPSW)	12/28/2022	18%
Cipher Mining (CIFR)	12/2/2022	17.28%
TMC the metals (TMC)	12/29/2022	17.1%

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