Unusual Options Activity: Bullish Trade on Citigroup

We noticed a big, bullish trade Wednesday on Citigroup (C). So far, the Oct. 62.5 and 75 calls and the Oct. 52.5 put have all traded more than 9,700 contracts, outstripping open interest at all three strikes by a wide margin. The 75 calls and 52.5 puts have traded at the bid or low in the bid-ask spread, while the 62.5 calls have traded high in the spread or at the ask. This indicates that this is likely a bullish debit spread with an additionional sold put.