If Mr. Hayes is tried or enters into a plea agreement in the U.S., British prosecutors wouldn't be able to try him on similar charges under U.K. double-jeopardy rules, according to criminal-defense lawyers who aren't involved in Mr. Hayes's case.

WSJ: U.S. and U.K. in Tussle Over Trader

Special Offer: Before you make new IRA contributions or rebalance your 401(k), double check to see which Fidelity funds--and fund managers--are the best places to put your capital.

FORBES: Gurus Square Off On Rates

Each DNA molecule in the body contains two long strands of chemical letters, or bases--A, T, C and G--that come together like a twisted ladder (a.k.a. the double helix).

FORBES: Magazine Article