Perpetua Resources (PPTA) had the highest return between 2021 and 2022 by a mid-cap US stock, returning 2,973.7%.

ASSET	YEARS	% RETURN
Perpetua Resources (PPTA)	2021-2022	2,973.68%
Alpha Metallurgical Resources (AMR)	2021-2022	1,245.02%
Peabody Energy (BTU)	2021-2022	973.96%
Weatherford International (WFRD)	2021-2022	757.95%
Baytex Energy (BTE)	2021-2022	720%
Applied Digital (APLD)	2021-2022	717.78%
Aehr Test Systems (AEHR)	2021-2022	704%
Vista Energy, SAB de CV (VIST)	2021-2022	504.63%
PBF Energy (PBF)	2021-2022	469.62%
SM Energy (SM)	2021-2022	467.09%
Calumet Specialty Products Partners (CLMT)	2021-2022	442.77%
Alliance Resource Partners (ARLP)	2021-2022	404.76%
Scorpio Tankers (STNG)	2021-2022	394.66%
Chord Energy (CHRD)	2021-2022	378.29%
Matador Resources (MTDR)	2021-2022	368.8%
Avis Budget (CAR)	2021-2022	334.71%
Torm PLC Class A (TRMD)	2021-2022	323.74%
Tidewater (TDW)	2021-2022	319.23%
Lantheus (LNTH)	2021-2022	277.2%
Murphy Oil (MUR)	2021-2022	267.24%
Northern Oil & Gas (NOG)	2021-2022	260.25%
Magnolia Oil & Gas (MGY)	2021-2022	232.98%
Patterson-UTI Energy (PTEN)	2021-2022	221.94%
Indivior PLC Ordinary Shares (INDV)	2021-2022	219.85%
Comstock Resources (CRK)	2021-2022	213.72%

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