Perpetua Resources (PPTA) had the best month in 2021 by a mid-cap US stock in January 2021, returning 7,836.8%.

ASSET	MONTH	% RETURN
Perpetua Resources (PPTA)	January 2021	7,836.84%
Trump Media & Technology (DJT)	October 2021	577.5%
Applied Digital (APLD)	April 2021	417.24%
Regencell Bioscience (RGC)	August 2021	278.36%
Immunome (IMNM)	February 2021	166.17%
Applied Digital (APLD)	January 2021	165.87%
Applied Digital (APLD)	October 2021	128.78%
Lucid (LCID)	January 2021	128.12%
Riot Platforms (RIOT)	February 2021	116.86%
Intellia Therapeutics (NTLA)	June 2021	114.17%
Nextdecade (NEXT)	June 2021	111.79%
BlackBerry (BB)	January 2021	110.45%
Xenon Pharmaceuticals (XENE)	October 2021	103.2%
Aehr Test Systems (AEHR)	July 2021	102.16%
Applied Digital (APLD)	February 2021	100%
Nuvalent (NUVL)	August 2021	96.92%
Upstart Holdings (UPST)	March 2021	92.96%
Celcuity LLC (CELC)	April 2021	90.76%
Upstart Holdings (UPST)	August 2021	87.8%
Tecnoglass (TGLS)	May 2021	87.31%
Ligand Pharmaceuticals (LGND)	January 2021	86.17%
Vera Therapeutics (VERA)	November 2021	85.11%
Regencell Bioscience (RGC)	November 2021	84.33%
Galaxy Digital (GLXY)	February 2021	84.01%
Aehr Test Systems (AEHR)	September 2021	82.98%

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