Citigroup stock price anomaly

Given that Abu Dhabi owns a great deal of Citigroup, this post may be of interest to followers of the UAE economy:

When the markets closed last Friday, the cost of buying 1,000 shares of Citigroup in these three ways were (using price quotes from Yahoo and ignoring transaction costs):

Method Cost

Simple $3,670

Preferred $3,052

Synthetic $3,160

Note: The preferred calculation is based on the Series F; other preferreds give slightly different values. The synthetic is based on options that mature in September 2009 with a strike price of $4.

What’s going on here? Why does it appear that investors in the common stock are overpaying by as much as 20%?