Amerant Bancorp (AMTB) had the highest return between 2000 and 2023 by a small-cap US stock, returning 7,953,100%.

ASSET	YEARS	% RETURN
Amerant Bancorp (AMTB)	2000-2023	7,953,100%
Diversified Energy (DEC)	2000-2023	6,206,850%
Gladstone Capital (GLAD)	2000-2023	911,150%
Sequans Communications (SQNS)	2000-2023	852,309.64%
Integra Resources (ITRG)	2000-2023	211,900%
Immatics (IMTX)	2000-2023	210,500%
NioCorp Developments Ltd Common Stock (NB)	2000-2023	187,547.06%
OPTIMIZERx (OPRX)	2000-2023	143,000%
Know Labs (KNW)	2000-2023	51,706.62%
Winmark (WINA)	2000-2023	13,188.59%
NAPCO Security Technologies (NSSC)	2000-2023	11,593.42%
Metalla Royalty & Streaming (MTA)	2000-2023	10,594.44%
Par Pacific (PARR)	2000-2023	5,961.67%
UFP Technologies (UFPT)	2000-2023	5,916.65%
Mesabi Trust (MSB)	2000-2023	5,368.37%
Greene County Bancorp (GCBC)	2000-2023	5,191.19%
Northrim BanCorp (NRIM)	2000-2023	4,496.07%
Helios Technologies (HLIO)	2000-2023	4,453.15%
Transcat (TRNS)	2000-2023	4,443.49%
Nathans Famous (NATH)	2000-2023	4,436.83%
USANA Health Sciences (USNA)	2000-2023	4,312.25%
Neogen (NEOG)	2000-2023	4,208.98%
John B Sanfilippo & Son (JBSS)	2000-2023	4,016.88%
US Physicalrapy (USPH)	2000-2023	3,901.99%
Sabine Royalty Trust (SBR)	2000-2023	3,855.35%

Small-cap stocks are treated as having a market cap between $300M and $2B.