Analyst Upgrades

• SuperValu (SVU) to buy from hold at Hapoalim.
• Constellation Energy (CEG) to buy from hold at Citigroup.
• Doral Financial (DRL) to neutral from sell and ABB (ABB) to buy from neutral at Sterne Agee.

Analyst Downgrades

• American Eagle (AEO) to neutral from buy at SunTrust.
• Tenet Healthcare (THC) to market perform from outperform at Wells Fargo.

Option traders appear to be setting up for a bullish move on ProLogis (PLD). Traders plowed into 1,067 new call option contracts -- 2.81 times the average volume -- on the stock on Thursday. And we know that traders were eager to get into this trade because 95% of the trades came in on the ask price.

ProLogis looks like it formed a bottom in early July and has since formed a higher low in August. The stock closed Thursday at $10.92, down 0.18% during the past month.

Option traders are pushing up call option prices in the Security Software & Services industry as well as pushing up put option prices in the Diversified Utilities industry today.

Any time the volatility skews above 1.00, it is an indication that calls are more expensive than puts. Typically, when calls are more expensive than puts, it means the demand for calls is greater than the demand for puts because investors believe the stock is going to rise in the future and they want to take advantage of that movement by buying calls.

Tenet Healthcare (THC) has admitted that it is in talks to acquire Healthscope -- the second-largest hospital corporation in Australia -- which is also being courted by Kohlberg Kravis Roberts (KKR) and a group of private equity firms that includes TPG, Carlyle and Blackstone (BX).

Tenet did not disclose what it was considering offering for Healthscope, but the other two offers from the private-equity bidders came in at approximately A$5.80 per share -- or A$1.84 billion total -- so it would be safe to assume that Tenet's offer would have to be somewhere close to that level.

Here are some highlights from this past week's earnings coverage on BloggingStocks:

• American International Group Inc. (AIG) posted a big loss and warned it may require additional assistance.
• Athenahealth (ATHN) shares sank after it delayed earnings and its annual report, and warned of restatements.
• Barnes & Noble Inc. (BKS) Q3 sales jumped on popularity of the Nook reader but same-store sales declined.
• Brocade Communications Systems Inc. (BRCD) disappointing report and guidance caused a sell-off in shares.
• Dell Inc. (DELL) acquisitions and better-than-expected earnings may not be enough to stop shrinking market share.
• Gap Inc. (GPS) rose after it beat earnings estimates, raised its dividend and announced stock buybacks.

Here are some highlights from last week's earnings coverage from BloggingStocks:

• CBS Corp. (NYSE: CBS) reported that Q3 revenue was flat while earnings and cash flow declined.
• Clorox Co. (NYSE: CLX) reported better-than-expected Q1 earnings, helped by healthy gross margins.
• Comcast Corp. (NASDAQ: CMCSA) posted better-than-expected Q3 earnings with modest revenue growth.
• Dean Foods Co. (NYSE: DF) Q3 revenue missed estimates but earnings came in better than expected.
• Expeditors International of Washington Inc. (NASDAQ: EXPD) traded lower after its Q3 earnings miss.
• Garmin Ltd. (NASDAQ: GRMN) beat earnings estimates in the week after the Google Navigation launch.

Dragged down by the challenging market conditions, many stocks have fallen under $10 lately. CNBC's Cindy Perman suggests that some of these stocks could be become good investments for traders. However, not everything that is cheap could be such a good bargain, Perman reminds us. You must always do your homework on potential investment before buying.

For example, Ford Motor (NYSE: F) fell down to around $6 compared with $38 nine years ago -- is it a good investment? Well, while the automaker revealed its plans to shift production from trucks to cars and give a boost to its turnaround plan, it also warned it won't be profitable until 2010 at the earliest.

Perman quotes several investment specialists on the matter. John Schloegel, vice president of investment strategies at Capital Cities Asset Management says, "An investment in Ford today feels like being in the wrong place at the wrong time." And Greg Womack, president of Womack Investment Advisers, advices to stay away from the sector, which doesn't look promising now, for the next three to five years to find out the "winner."

Monday August 6

• Blue Nile Inc (NASDAQ: NILE) to report Q2 earnings; conference call at 5pm.
• SINA Corporation (NASDAQ: SINA) to report Q2 earnings; conference call at 9pm.

Tuesday August 7

• Tenet Healthcare Corporation (NYSE: THC) to report Q2 earnings; conference call at 11am.
• Cisco Systems Inc (NASDAQ: CSCO) to report Q4 earnings; conference call at 4:30pm.

Wednesday August 8

• Sprint Nextel Corporation (NYSE: S) to report Q2 earnings; conference call at 8am.
• Hot Topic Inc (NASDAQ: HOTT) to report monthly sales at 4pm.

Thursday August 9

• More monthly sales reports, including: Chicos FAS Inc (NYSE: CHS) at 7:30am; Limited Brands Inc (NYSE: LTD) at 7:30am; Wal-Mart Stores Inc (NYSE: WMT) at 8am; AnnTaylor Stores Corporation (NYSE: ANN) at 8am; and Abercrombie & Fitch Co (NYSE: ANF) at 8:15am.

Friday August 10

• EchoStar Communications Corporation (NASDAQ: DISH) to report Q2 earnings; conference call at 12pm.
• PDUFA date for Solvay SA (OTC: SVYSY) and Wyeth's (NYSE: WYE) Bifeprunox for the treatment of Schizophrenia.