You're describing part of a tax-management strategy: sell bonds in the US, secured by cash in an offshore tax haven (e.g., Ireland), use the proceeds to return cash to shareholders, pay the bond coupons out of cash flow, and write off the interest payments. It has everything to do with the pile of cash when it's cheaper to use debt secured by the cash than to pay taxes to repatriate the cash. If worse comes to worst, the cash is still there to make bond-holders whole.