If you are looking for clues to tell 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.

Mattson Technology (MTSN) topped the insider-buying charts for the week ending Feb. 25 as insiders snapped up 5,000,000 shares of company stock at a market value of $12,350,000. During the past six months, insiders have increased their overall holdings in the company by -6.49% and now own 0.14% of MTSN stock.

Analyst upgrades:

• Stephens upgraded Quidel (QDEL) to equal weight from underweight on valuation following the recent pullback in shares. The firm keeps a $16 price target on the stock.
• UBS upgraded Clearwire (CLWR) to neutral from sell, citing the company's funding, which increases opportunities. The firm raised its price target to $6 from $3.
• Oppenheimer upgraded Mattson Technology (MTSN) to outperform from perform on expectations the company will benefit from a cyclical recovery in memory capex spending in 2010. The firm raised its target on shares to $4 from $3.
• Eli Lilly (LLY) was upgraded to sell from conviction sell at Goldman.
• Kinross Gold (KGC) was upgraded to overweight from neutral at JPMorgan.
• Limited Brands (LTD) was upgraded to hold from sell at Soleil.

Analyst upgrades:

• UBS believes US airlines estimates are too low and will move higher. The firm upgraded AirTran (NYSE: AAI), AMR Corp (NYSE: AMR), Continental (NYSE: CAL), Delta (NYSE: DAL) and Northwest (NYSE: NWA) to Buy from Neutral and JetBlue (NASDAQ: JBLU) to Neutral from Sell.
  
• JMP Securities upgraded DealerTrack (NASDAQ: TRAK) to OUtperform from Market Perform as they believe 2H08 guidance represents a floor and that 2009 estimates are achievable, among other reasons.
• Potash (NYSE: POT) and Mosaic (NYSE: MOS) were raised to Buy from Hold at Soleil.
  
• Argus upgraded Seagate (NYSE: STX) to Buy from Hold on Friday.

Analyst downgrades:

• Jefferies downgraded Citrix Systems (NASDAQ: CTXS) to Underperform from Hold as they do not see a catalyst for the company to grow into 2009 consensus estimates. The firm lowered their target price to $25 from $32.
  
• Citigroup said following Lehman's (NYSE: LEH) bankruptcy, they expect a distressed-sale of American International's (NYSE: AIG) MBS portfolio, resulting in the worst quarter yet for the company. Shares were cut to Hold from Buy.
• D.R. Horton (NYSE: DHI) was downgraded to Sell from Hold and Pulte Homes (NYSE: PHM) was downgraded to Hold from Sell at Citigroup.
  
• Merrill downgraded Goldman Sachs (NYSE: GS) to Neutral from Buy and JP Morgan (NYSE: JPM) to Underperform from Neutral.

MOST NOTEWORTHY: Advantest (ATE), RightNow Technologies (RNOW), Mattson Technology (MTSN), Akamai Technologies (AKAM) and P.F. Chang's (PFCB) were today's noteworthy downgrades:

• Matrix downgraded Advantest (NYSE: ATE) to Strong Sell from Hold; the firm doesn't expect Advantest's profits to improve in the near-term after chip makers indicated they plan to cut capital spending.

• RightNow Technologies (NASDAQ: RNOW) was cut to Sector Perform from Outperform at Pacific Crest to reflect the company's poor execution.

• Mattson Technology (NASDAQ: MTSN) was downgraded to Sell from Buy at American Technology; The firm said Q2 results were strong but bookings and gross margin outlook were weaker due to memory spending weakness.

• Credit Suisse downgraded P.F. Chang's (NASDAQ: PFCB) to Market Weight from Overweight at Thomas Wiesel to reflect below plan new store performance for the third consecutive year at Pei Wei...

OTHER DOWNGRADES:

• Citigroup cut Taiwan Semi (NYSE: TSM) to Hold from Buy.

• Merriman downgraded Fuel Tech (NASDAQ: FTEK) to Neutral from Buy.

• Bear Stearns cut Hess Corp (NYSE: HES) to Peer Perform from Outperform.

• Goldman Sachs removed Merrill Lynch (NYSE: MER) from its Conviction Buy list.

Analyst summaries provided by TheFlyOnTheWall.com (subscription required).