An oil pump works at sunset in the desert oil fields of Sakhir, Bahrain, in October. The price of oil has fallen about 40 percent since mid-June. (Hasan Jamali/AP) Tumbling oil prices are draining hundreds of billions of dollars from the coffers of oil-rich exporters and oil companies and injecting a much-needed boost for ailing economies in Europe and Japan — and for American consumers at the start of the peak shopping season . The result could be one of the biggest transfers of wealth in history, potentially reshaping everything from talks over Iran’s nuclear program to the Federal Reserve’s policies to further rejuvenate the U.S. economy. The price of oil has declined about 40 percent since its peak in mid-June and plunged last week after the Organization of the Petroleum Exporting Countries voted to continue to pump at the same rate. That continued a trend driven by a weak […]