After Clinton, Greenspan and the tech stock boom/bubble balanced the budget there was a shortage of safe assets, to the private market in collusion with the ratings agencies created the shadow banking system with mortgage-backed securities and sold them as safe.
Bernanke has said he might have been wrong to call this a "global savings glut." There's something else going on on the flip side, a dearth of investment and asset prices move higher. Interest rates move lower. But Beckworth says interest rates remain the same, it's just the risk premium goes up.