WM Technology (MAPSW) had the best day in December 2023 by a mid-cap US stock on December 29, 2023, returning 44.2%.

ASSET	DATE	% RETURN
WM Technology (MAPSW)	12/29/2023	44.23%
American Bitcoin (ABTC)	12/27/2023	41.62%
Advantage Solutions (ADVWW)	12/19/2023	36.36%
Liquidia Technologies (LQDA)	12/20/2023	35.1%
ACADIA Pharmaceuticals (ACAD)	12/13/2023	32.42%
Sezzle (SEZL)	12/22/2023	29.7%
CleanSpark (CLSK)	12/1/2023	29.27%
Sezzle (SEZL)	12/19/2023	27.99%
Mercurity Fintech Holding Inc ADR (MFH)	12/5/2023	26.61%
Eos Energy Enterprises (EOSE)	12/13/2023	25.42%
Applied Opt (AAOI)	12/1/2023	24.72%
PureCycle Technologies (PCTTW)	12/20/2023	24.71%
Compania de Minas Buenaventura SAA ADR (BVN)	12/15/2023	23.4%
Cipher Mining (CIFR)	12/18/2023	23.14%
Mercurity Fintech Holding Inc ADR (MFH)	12/4/2023	22.92%
Upstart Holdings (UPST)	12/1/2023	22.24%
Cytokinetics (CYTK)	12/21/2023	21.14%
Grupo Aeroportuario del Sureste SAB de CV ADR (ASR)	12/14/2023	21.01%
Purecycle Technologies (PCT)	12/19/2023	20.89%
Cipher Mining (CIFR)	12/26/2023	20.87%
Sunrun (RUN)	12/13/2023	20.74%
Upstart Holdings (UPST)	12/13/2023	20.07%
Bitdeer Technologies Group Class A Ordinary Shares (BTDR)	12/15/2023	19.7%
Immunitybio (IBRX)	12/12/2023	19.61%
Mercurity Fintech Holding Inc ADR (MFH)	12/29/2023	19.27%

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