U.S. equity markets ended the week of Aug. 16-20 mixed following somewhat volatile trade. With three up days followed by two down days the week finished lower.

The sector breakdown was mostly negative, as seven of the 10 S&P groups ended lower, led by energy (-2.3%). Only technology (+0.7%), consumer discretionary (+0.6%) and materials (+0.4%) managed to finish slightly higher.

Markets regained opening losses on Monday, rallied on Tuesday, was up and down on Wednesday to finish a little higher, sold off hard on Thursday and did a mild comeback on Friday, still finishing lower.

Retailers Walmart (WMT) and Home Depot (HD) reported earnings this week with results and guidance mixed.

This week we also had Potash (POT) announce that it rejected a takeover offer from BHP Billiton (BHP). That offer was for $130 per share in cash, a 16% premium to the prior session's closing price. Shares of POT surged more than 27% on the announcement. BHP did not give up and appealed to POT shareholders through a newspaper advertisement before taking the bid hostile.

The POT/BHP story led to a renewed batch of M&A speculation. Next we had Intel (INTC) acquired McAfee (MFE) on Thursday morning in a cash transaction for a 60% premium.

Nnext week on the economic calendar we have existing home sales on Tuesday, durable goods orders on Wednesday, initial jobless claims on Thursday and the second reading for Q2 2010 GDP on Friday. The Treasury market will have the next round of auctions. $7 billion in 30-year TIPS will reopen on Monday, followed by $102 billion in 2-, 5- and 7-year Notes going on sale Tuesday through Thursday.

DJIA: Down -0.9% for the week.
Nasdaq: Up 0.3% for the week.
S&P 500: Down -0.7% for the week.
Russell 2000: Up 0.2 % for the week.