Jefferson County has come out on the short end of a complicated and convoluted series of bond swaps by more than $150 million, and the county has overpaid investment bankers tens of millions in fees on the deals, according to a report compiled by Porter, White & Company and distributed to the county commission today.

“Jefferson County’s swap portfolio had a negative mark-to-market value of $151.7 million as of December 31, 2006,” the report said.

Bond swaps are extremely complicated and not well understood outside of a small number of highly specialized traders at some of the country’s biggest investment banks, many of which have done business with the county. In a simplified sense, a bond swap is much like trading a fixed-rate credit card for a floating-rate card, only in this case the debt can range in the billions.

Since the election of the last county commission in 2002, Jefferson County’s bond swap portfolio has grown to be one of the largest in the county, exceeding those even of many states. What’s more, conspicuous political connections between some of the investment bankers and county commissioners have made the swap deals a matter of interest for several federal agencies.

Officials from Porter, White & Co. told the commission that the county had overpaid investment bankers by as much as $100 million.