I apologise for offending you, but this is widely considered to be fact, but if you would like me to recalculate i can, 4 exoticshave been sold by xur for warlock. 1/4: 25% chance 25% = 0.25 0.25 * 0.25 * 0.25 * 0.25 = 0.00390625 0.00390625 = 0.390625% chance of it being sold, assuming Xur only sells these four exotics, still around a 3 in 1000 chance