From Phil's Stock World (Thursday):
C - Citigroup, Inc. – One investor established a mammoth bullish stance on Citigroup in the first 20 minutes of the current trading session. Citigroup’s shares at the time of the transaction were trading at approximately $4.05, but have since slipped lower and are down 0.50% to $4.03 as of 2:45 pm (ET). It looks like the Citi-bull sold 240,000 put options outright at the April $4.0 strike to take in a premium of $0.16 per contract. Premium received on the sale, which represents maximum potential profits, amounts to $3.840 million to the investor if Citigroup’s shares trade above $4.00 through expiration day. The short stance in put options implies the investor is willing to have 24 million shares of the underlying stock put to him at an effective price of $3.84 each should the puts land in-the-money at expiration.