As of September 6, 2014, Ripple Singapore's (RS's) IRBA page states -34.86 XAU balance and 40 XAU in reserves. Ripple Charts (Capitalization, XAU) shows about 51.9 at this time. Why the difference? (Or does Ripple Charts' Capitalization mean something else?)

I imagine this might come from rippling, though don't know exactly how. I'd still imagine that someone's (eg. RS's) new IOU's can only be issued when they explicitly send the currency to someone else; rippling should only swap different peoples IOU's and not create new ones, right?

Does the difference in balances mean that RS, in addition to bullion in their safes, also holds other peoples XAU IOU's to cover for the difference?