The updated US TIC numbers for January 2014 reveal Belgium to be the third-largest holder of Treasuries. Note that Russia hasn't dropped off the list just yet; we'll have to wait until the March TIC data release in May to see if some oligarchs are moving around. Anyway, note that the line for "Caribbean Banking Centers" really refers primarily to the hedge funds domiciled there, not the island countries' sovereign cash. The line for Belgium probably means much the same. GlobalFundData notes that there are plenty of hedge funds in Belgium. The Treasury press release for today's TIC data refers to "foreign residents" rather than sovereign governments. Maybe a bunch of European aristocrats used their family banks to buy Treasuries. They probably got a good deal as the Fed began backing away from its QE role.
We have nothing to fear from Belgium. Zero Hedge can relax.