A High-risk/High-reward Bullish Options Trade in Citigroup (C)

From optionsXpress via Daily Markets:

...Bullish FlowThe top equity options trades Friday were in Citigroup (C: 4.29 -0.07 -1.61%). It was part of a spread. Shares lost 7 cents to $4.29 on the session and one strategist apparently bought the June 4.5 – 5.5 call spread for a net debit of 30 cents, 56800X.

That is, they bought 56800 June 4.5 calls at 47 cents and sold 56800 June 5.5 calls at 17 cents. It looks like a new spread because volume exceeds open interest in both contracts. It also looks like an aggressive high risk-high reward play. This net cost is 30 cents (excluding commissions) and the possible pay-off is $1.70 if shares rally to $5.5 (28.2 percent) or more by the June options expiration. If shares fail to move above $4.5, the entire debit is at risk.