For me the “Savings Glut” Hypothesis falls down on a number of key areas:
The first and most important is that it appears to ignore significant loan/monetary growth which breaks the point in time National Income Identity on which “Savings Glut” arguments apparently rest. I say apparently because much of the discourse supporting the SG hypothesis is either couched in nuanced semantic surfing and/or bereft of argument that you can trace directly back to the source of the flows from which they derive savings. Many supporters of the SG hypothesis either ignore these monetary dynamics totally or disavow them without cause.
The second is that it ignores the foreign exchange and central bank monetary dynamics involved in much of the FX/asset purchases. Key components of the trade balance/net investment position were orchestrated by Central banks creating new money to buy dollars and thence assets.
The third is that it ignores the fact that the major mega surplus economy, China, was and remains to a very large extent driven by loan financed (new money) gross fixed capital investment. Again the basic National Income Identity model misses a myriad of inter temporal dynamics. The SG argument was that it was excess savings and not monetary and financial system excess that caused the crisis and to fully understand the imbalances you have to look at where National Income/output is derived.
The fourth is that it ignores the very important development of emerging Asia as a global production hub and the off shoring dynamics that saw significant components of US and other international manufacturers move tranches of their manufacturing base to these countries. This issue is well covered and documented.
Finally, as discussed in numerous papers, focussing only on the net investment flows ignores vast sources of excess demand for assets that were also instrumental in pushing financial markets out of synchonisation with their economic fundamentals.
I will look to explore and illustrate these arguments in coming posts.