Analysts are weighing in today on alternative energy issue LDK Solar Co., Ltd. (NYSE:LDK - 1.84), Linux specialist Red Hat, Inc. (NYSE:RHT - 51.36), and drugstore chain Walgreen Company (NYSE:WAG - 29.94). Here's a quick roundup of today's bearish brokerage notes.

• Piper Jaffray weighed in on a slew of solar stocks today, with LDK targeted for a downgrade to "underweight" from "neutral" and a price-target cut to $1 from $2.50. The downwardly revised target represents a discount of 45.7% to Wednesday's close at $1.84. Piper Jaffray isn't the only brokerage firm betting on a deeper decline from LDK, which has shed nearly 72% of its value over the past 52 weeks. The stock's average 12-month price target stands at $1.60, with not one analyst out of five deeming LDK worthy of a "buy" rating.
  
  
• RHT was hit with a downgrade to "perform" from "outperform" at Oppenheimer, as the brokerage firm is apparently unimpressed by the equity's year-to-date rally of 24.4%. The shares are off 1.3% ahead of the bell, but RHT is hovering above solid technical support. Specifically, the stock has lately been aided by its rising 40-week moving average and the round-number $50 level, both of which are directly underfoot.
  
  
• ISI Group started coverage of WAG with an "underweight" rating, representing yet another negative note for the pharmacy chain. Already, 10 analysts out of 19 have slapped the stock with a "hold" or "sell" rating. WAG is down 9.4% so far in 2012, and the security is currently trading just below resistance at its descending 20-day moving average and the $30 level.