Lam Research (LRCX) had the highest return in January 2001 by a mega-cap US stock, returning 77%.

ASSET	MONTH	% RETURN
Lam Research (LRCX)	January 2001	76.99%
Advanced Micro Devices (AMD)	January 2001	74.16%
NVIDIA (NVDA)	January 2001	56.51%
SAP SE ADR (SAP)	January 2001	47.44%
Apple (AAPL)	January 2001	45.43%
Microsoft (MSFT)	January 2001	38.38%
Taiwan Semiconductor Manufacturing (TSM)	January 2001	33.19%
International Business Machines (IBM)	January 2001	32.54%
Applied Materials (AMAT)	January 2001	29.63%
ASML Holding NV ADR (ASML)	January 2001	28.81%
Micron Technology (MU)	January 2001	24.54%
JPMorgan Chase (JPM)	January 2001	24.13%
Intel (INTC)	January 2001	20.57%
Bank of America (BAC)	January 2001	18.77%
Costco Wholesale (COST)	January 2001	15.62%
Novo Nordisk A-S (NVO)	January 2001	12.52%
Amazon (AMZN)	January 2001	9.47%
Goldman Sachs (GS)	January 2001	9.1%
Morgan Stanley (MS)	January 2001	8.67%
Toyota Motor Corporation ADR (TM)	January 2001	8.2%
Citigroup (C)	January 2001	8.15%
Walt Disney (DIS)	January 2001	7.08%
HSBC Holdings PLC ADR (HSBC)	January 2001	6.44%
Home Depot (HD)	January 2001	5.5%
Intuitive Surgical (ISRG)	January 2001	3.07%

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