Billionaire investor Carl Icahn spent months trying to buy Dynegy (DYN), but the transaction fell apart. There are always more deals though, right? Well, Icahn is now making a bid for Mentor Graphics (MENT).

He is proposing $1.73 billion for the company or $17 per share. In fact, Icahn already has a 14.7% stake. And as should be no surprise, the shares of Mentor are up about 11%.

Analyst Upgrades

• Goldman upgraded Citigroup (C) to conviction buy from buy, Principal Financial (PFG) to buy from neutral, and Stancorp Financial (SFG) and Hartford Financial (HIG) to neutral from sell.
• JetBlue (JBLU) was upgraded to overweight from neutral at JPMorgan.
• Barclays upgraded Royal Caribbean (RCL) and Carnival (CCL) upgraded to overweight from equal weight.
• Hollysys Automation (HOLI) was upgraded to buy from hold at Roth Capital.
• RBC Capital upgraded Alliance Data Systems (ADS) to outperform from sector perform.
• RRI Energy (RRI) was upgraded to buy from hold at Citigroup.

If you are looking for clues telling you which stocks have a good chance of increasing in value, you might want consider watching what insiders are doing. After all, talk is cheap, but when insiders put their own money on the line, you should sit up and take note.

Take-Two Interactive Software Inc (TTWO) topped the insider-buying charts for the week ending July 9 as insiders snapped up 427,900 shares of company stock at a market value of $4,093,939. During the past six months, insiders have increased their overall holdings in the company by 64.15% and now own 2.74% of TTWO stock.

For the most part, the Cadence Design Systems (NASDAQ: CDNS) unsolicited offer for Mentor Graphics (NASDAQ: MENT) was a smart move (both companies are leaders in semiconductor design software). This transaction would be a critical part of consolidation in the industry.

However, on Friday, Cadence decided to drop its $1.6 billion bid. As a result, the shares of Mentor plunged 25%.

What happened here? Well, according to Cadence, it looks like the board of Mentor didn't want to open its books (although, Mentor disputes this). Another issue is antitrust. Oh, and with the credit crunch, it's still pretty tough getting financing.

Perhaps the big problem is the slowing economy, which is putting pressure on the semiconductor industry. After all, Cadence posted weak Q2 results, and the outlook looks dismal.

Whatever the reasons, Wall Street likes the result. On the news, Cadence's share increased 6.7%.

Tom Taulli is the author of various books, including The Complete M&A Handbook and The Edgar Online Guide to Decoding Financial Statements. He also operates MergerBook.com.

Another low volume August trading day is behind us. Markets in the US responded rather well to economic data but falling oil prices and gold prices are beginning to take over in importance. Oil was down again and gold followed suit. There was generally still a mixed market most of the day. After what we have been seeing for longer than many care to remember we'd consider a mixed day a partial win. Here are today's unofficial closing bell levels:

• DJIA 11,659.90 +43.97 (0.38%)
  
• S&P500 1,298.19 +5.26 (0.41%)
• NASDAQ 2,452.52 -1.15 (-0.05%)
• 10YR T-Note 3.852% (-0.04%)
• 52-WEEK LOWS
• Top Analyst Upgrades
• Top Analyst Downgrades

Mentor Graphics (NASDAQ: MENT) was down 25% at $10.41 in today's final minutes. Its buyout has fallen through. The cause: financing issues. Go figure.

Cadence Design Systems Inc. (NASDAQ: CDNS) is the largest player in developing platforms for building integrated circuits. The company generates about $1.6 billion in revenues and has 5,100 employees.

Now, Cadence wants to get even bigger. Today, the company announced an unsolicited $1.6 billion bid for Mentor Graphics Corp. (NASDAQ: MENT). The offer is $16 per share.

Mentor is a big player in testing semiconductors, which should be a nice compliment to Cadence. And over the past couple months, Cadence has been trying to court Mentor.

But all advances were rejected. So why not go hostile?

MOST NOTEWORTHY: NICE Systems, Watson Pharmaceuticals and Micron Tech were today's noteworthy upgrades:

• NICE Systems (NASDAQ: NICE) was upgraded to Buy from Neutral at UBS, as they believe NICE is well-positioned to leverage its offerings in VoIP recording, call centre analytics, and other applications with its extensive enterprise customer base.
  
• Hambrecht upgraded shares of Watson Pharmaceuticals (NYSE: WPI) to Buy from Hold ahead of the company's Q4 results to reflect valuation and low expectations.
  
• Thomas Weisel upgraded Micron Tech (NYSE: MU) to Overweight from Market Weight citing expectations DRAM pricing will stabilize in 2008, potential upside from high growth DRAM segments such as mobile, and notes cost cutting efforts and valuation.

OTHER UPGRADES:

• JP Morgan added Wabtec (NYSE: WAB) to its Focus List.
  
• Keefe Bruyette raised Franklin Bank (NASDAQ: FBTX) to Market Perform from Underperform.
  
• Morgan Stanley upgraded Wyeth (NYSE: WYE) to Overweight from Equal Weight.
  
• Citigroup upgraded Mentor Graphics (NASDAQ: MENT) to Buy from Hold and added shares to its Top Picks List.

My recent Investing in Oregon post took a look at some companies that the Motley Fool had featured in its investigation of investment opportunities in the Beaver State, including Precision Castparts Corp. (NYSE: PCP), StanCorp Financial Group Inc. (NYSE: SFG), FLIR Systems Inc. (NASDAQ: FLIR), and Columbia Sportswear Co. (NASDAQ: COLM).

But the Motley Fool article also mentioned that one of the most prominent business influences in Oregon wasn't even headquartered in the state: semiconductor giant Intel Corp. (NASDAQ: INTC) from Santa Clara, California. It also included mention of four Oregon-based businesses that provided support for Intel: Tektronix Inc. (NYSE: TEK), Mentor Graphics Corp. (NASDAQ: MENT), Triquint Semiconductor Inc. (NASDAQ: TQNT), and Electro Scientific Industries Inc. (NASDAQ: ESIO). One could imagine that Intel's impressive earnings report this week should have been good news for these supporting companies.

Beaverton-based Tektronix, widely known as Tek, is one of the leading makers of test and measurement equipment, such as digital multimeters, logic analyzers, and curve tracers, and oscilloscopes. Tek will win its seventh technical Emmy this year. Tek beat Wall Street expectations in its previous three quarters, reporting earnings per share of 40 cents for its first quarter FY2008. But the consensus of analysts surveyed by Thomson Financial was to hold shares of Tek. The share price reached a 52-week high of $37.95 on Monday when it was announced that Danaher Corp. (NYSE: DHR) will acquire Tek. Tool and equipment maker Danaher just announced record third quarter results.

The design of electronic hardware components has become so intricate a process that engineers use digital simulation products to avoid long verification cycles and the expense of manufacturing multiple prototypes. A leading provider of design automation software and systems is headquartered in Wilsonville, Oregon.

Mentor Graphics (NASDAQ: MENT) provides electronic design automation software and systems that engineers use to design, analyze, simulate, model, implement and verify the components of electronic systems. Firms use Mentor's software to produce such products as computers, routers, and cellular handsets. The company also provides consulting and support services. Mentor has business partnerships with Hewlett-Packard (NYSE: HPQ) and Sun Microsystems (NASDAQ: JAVA).

The firm pleased investors last week, when it reported Q2 EPS of 15 cents and revenues of $205.7 million. Analysts had been expecting 8 cents and $200.2 million. The CEO noted strength across all of the company's system related product lines. Management also guided FY08 EPS to $1.02 (98 cent consensus), FY08 revenues to about $860 million ($856.04M consensus), FY09 EPS to $1.22 ($1.15 consensus) and FY09 revenues to about $920 million ($912.44M consensus).