WASHINGTON - The United States on Wednesday warned European banks, investors and businesses against engaging with the so-called special purpose vehicle (SPV), a Europe-backed system to facilitate non-dollar trade with Iran and circumvent US sanctions. 'If you are a bank, an investor, an insurer or other business in Europe you should know that getting involved in the … Special Purpose Vehicle is a very poor business decision,' Tim Morrison, Special Assistant to the President and Senior Director for Weapons of Mass Destruction and Biodefense told a conference. He has also called Iran's move to scale back some curbs to its program 'nothing less than nuclear blackmail of Europe.'