One view holds that long-term growth risks have been on the rise, raising the premium on assets that are perceived to be relatively safe, and raising precautionary saving in general. (Of course, no one should think that any government bonds are completely safe, particularly from inflation and financial repression.)
解释这一现象的理论有很多，大多颇为漂亮，但没有一个彻底令人满意。一种观点是长期增长风险在上升，提高了被认为相对安全的资产的溢价，也提高了总体预防性储蓄。（当然，政府债券也并非完全安全，特别是考虑到通胀和金融抑制的情况。）毫无疑问，2008年金融危机不啻对“大稳健”观点（长期波动性下降）的警钟。许多研究表明，锚定长期增长趋势预期正变得前所未有地困难。比如，关于技术进步在加速还是在减速的问题就存在激烈争论。地缘政治实力的变迁也在滋生不确定性。