How a fancy diamond helped Nirav Modi in India's biggest bank fraud

The rapid-fire sales were described as part of a plan in which Modi and associates "fraudulently borrowed approximately $4 billion over a period of years

The price of the large yellow diamond alternately shrank and spiked by about a million dollars as it moved across the globe.

The three-carat gem was shipped at least four times between shadowy companies allegedly controlled by Indian billionaire Nirav Modi over about five weeks in 2011, according to a report by a US bankruptcy examiner. The practice of round-tripping--trading a good repeatedly to give the appearance of distinct transactions--was central to the largest bank fraud in Indian history and ensuing criminal charges against celebrity jeweler Modi, according to the report filed Aug. 25.

The rapid-fire sales were described as part of