Tesla (TSLA) had the highest return between 2019 and 2021 by a mega-cap US stock, returning 1,626.2%.

ASSET	YEARS	% RETURN
Tesla (TSLA)	2019-2021	1,626.2%
NVIDIA (NVDA)	2019-2021	806.3%
Advanced Micro Devices (AMD)	2019-2021	699%
Lam Research (LRCX)	2019-2021	464.58%
ASML Holding NV ADR (ASML)	2019-2021	431.95%
Applied Materials (AMAT)	2019-2021	410.49%
Apple (AAPL)	2019-2021	372.38%
Taiwan Semiconductor Manufacturing (TSM)	2019-2021	263.19%
Microsoft (MSFT)	2019-2021	249.77%
Thermo Fisher Scientific (TMO)	2019-2021	205.63%
Micron Technology (MU)	2019-2021	201.22%
Broadcom (AVGO)	2019-2021	198.96%
Costco Wholesale (COST)	2019-2021	198.16%
Alphabet Inc Class A (GOOGL)	2019-2021	182.03%
Morgan Stanley (MS)	2019-2021	173.02%
Home Depot (HD)	2019-2021	162.5%
Facebook (META)	2019-2021	160.76%
Novo Nordisk A-S (NVO)	2019-2021	159.22%
Eli Lilly and (LLY)	2019-2021	154.78%
Goldman Sachs (GS)	2019-2021	147.59%
Netflix (NFLX)	2019-2021	132.35%
Intuitive Surgical (ISRG)	2019-2021	129.58%
Amazon (AMZN)	2019-2021	127.57%
UnitedHealth (UNH)	2019-2021	114.83%
Abbott Laboratories (ABT)	2019-2021	109.66%

Mega-cap stocks are treated as having a market cap of $200B+.