In his latest missive to investors (pdf link here), Eric Sprott asks if our Ponzi economy is at risk of collapse. In fiscal 2009, foreigners scooped up $698 billion of Treasuries while the Fed upped its holdings by $286 billion. But the public debt increased $1.9 trillion. So who bought all the rest? According to Treasury, “other investors” bought $510 billion, up from just $90 billion in 2008. With the Fed’s printing press turned off, the question for next year is whether “other investors” can buy more Treasuries than they did this year…