WAG – Walgreen Co. – Shares of the largest drugstore chain in the U.S. fell 2.35% to $29.13 today after Barclays cut WAG’s 2011 earnings estimate to $2.05 from $2.55 following CVS Caremark Corp.’s decision to speed up Walgreen’s exit from its retail pharmacy network. Additionally, Barclays reduced their share price estimate on WAG to $27.00 from $36.00. Bearish options investors burst right out of the gate this morning to populate Walgreen with pessimism. One investor enacted a bearish risk reversal, while other traders purchased plain-vanilla puts in the June contract. Put buyers picked up approximately 1,900 contracts at the June $29 strike for an average premium of $0.71 apiece. Investors long the puts make money if Walgreen’s shares decline another 2.9% to breach the average breakeven point to the downside at $28.29 by June expiration day. The risk reversal strategist appears to have sold 1,500 calls at the June $30 strike for a premium of $0.24 each in order to partially finance the purchase of the same number of puts at the lower June $28 strike for an average premium of $0.41 apiece. Net premium paid for the transaction amounts to $0.17 per contract. Thus, the investor responsible for the trade is prepared to profit should shares of the underlying stock fall another 4.5% from the current price of $29.13 to trade beneath the effective breakeven price of $27.83 by expiration.