Salesforce (CRM) had the highest return in August 2006 by a mega-cap US stock, returning 34.7%.

ASSET	MONTH	% RETURN
Salesforce (CRM)	August 2006	34.74%
NVIDIA (NVDA)	August 2006	33.09%
Advanced Micro Devices (AMD)	August 2006	27.18%
Cisco Systems (CSCO)	August 2006	23.12%
Mastercard (MA)	August 2006	21.73%
Novo Nordisk A-S (NVO)	August 2006	18.67%
Amazon (AMZN)	August 2006	16.12%
ASML Holding NV ADR (ASML)	August 2006	12.38%
Procter & Gamble (PG)	August 2006	10.54%
UnitedHealth (UNH)	August 2006	9.37%
Royal Bank of Canada (RY)	August 2006	9.14%
AstraZeneca PLC ADR (AZN)	August 2006	7.86%
Taiwan Semiconductor Manufacturing (TSM)	August 2006	7.63%
Microsoft (MSFT)	August 2006	7.39%
International Business Machines (IBM)	August 2006	6.06%
SAP SE ADR (SAP)	August 2006	5.27%
LIN TV (LIN)	August 2006	5.24%
Berkshire Hathaway (BRK.B)	August 2006	5.14%
Oracle (ORCL)	August 2006	5.1%
Berkshire Hathaway (BRK.A)	August 2006	4.91%
GE Aerospace (GE)	August 2006	4.32%
Johnson & Johnson (JNJ)	August 2006	4.26%
Toyota Motor Corporation ADR (TM)	August 2006	4.09%
AT&T (T)	August 2006	3.08%
Abbott Laboratories (ABT)	August 2006	2.63%

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