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The PBOC faces the Impossible Trinity

The Impossible Trinity or Trilemma is a trilemma in international economics which states that it is impossible to have all three of the following at the same time:
 
  • A fixed foreign exchange rate
  • Free capital movement (absence of capital controls)
  • An independent monetary policy

When the PBOC buys dollar assets, they do so by increasing the Chinese domestic monetary base (the domestic banking system's yuan reserve balance) which puts downward pressure on Chinese interbank interest rates.  In order to target a specific FX rate the PBOC must accumulate foreign exchange reserves when their current account surplus is greater than the capital account deficit.  This is what it means to have a positive balance of payments. 

On the other side of these balances are China's trading partners who must run corresponding negative balance of payments.  In other words, countries like the US end up running large current account (trade) deficits.  Bernanke wrote a series of posts that were critical of countries that attempted to perpetually accumulate foreign reserves as this practice reduces global aggregate demand relative to supply. 

Now consider the opposite scenario where​ Chinese policy changes by prioritize domestic liquidity conditions by adding yuan reserves to their banking system through domestic open market operations that work to offset the sale of any dollar assets off of the PBOC's balance sheet.  This would put downward pressure on Chinese interest rates relative to what would occur if the PBOC were to solely sell off dollar assets in order to stabilize the FX rate.* What this also does is release a supply of safe dollar t-securities at a time where dollar demand relative to supply has been elevated as witnessed by the rapid appreciation of the dollar against most currencies.  If anything this should alleviate tight global dollar financial conditions.  

​Moreover, if policies that have led to the persistent accumulation of foreign exchange reserves have reduced global aggregate demand and thereby inflation and LT interest rates (via the term premium) in developed markets for over a decade, then I would suspect that any deaccumulation should boost global demand. In the process this boost to global aggregate demand should close global output gaps enough to possibly reverse the disinflationary trends and weak wage growth witnessed in the developed world.  

Therefore, what may be best for global demand would be for China to ease domestic monetary conditions by increasing their domestic reserve balances within their banking system until they stabilize the deceleration in nominal GDP.  As this would likely induce capital flight, the PBOC should sell off their dollar assets while simultaneously responding by buying Chinese government securities to offset any monetary tightness. 
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​A Chinese economic rebalancing away from export and investment lead growth to an economy that is more geared toward Chinese domestic consumption does not necessarily need to translate to slowing global growth.  If anything, the rise of the Chinese consumer should create a new source of demand.  

​As for any comparison between PBOC dollar/t-security selling to the reversal of the Fed's QE program which would also involve the sale of t-securities, these are not the same.  Yes selling dollar assets off of PBOC's balance sheet would act as a domestic monetary tightening, but they could improve liquidity conditions in China by buying yuan securities to offset these dollar sales.  I suspect that the move away from tightly managing the FX rate is to signal that this is in fact what they plan to do where Chinese monetary policy will be more oriented toward steering domestic interest rates as the main policy lever.**

​On the other hand, if the Fed were to reverse their previous asset purchases it would be because they feel that US NGDP, employment, and inflation are expected to increase at a pace that is above their mandates.  In other words, in that state of the world, US economic activity would be much better than what we are currently experiencing.  ​The Fed would be signaling that their balance sheet would be set to shrink because US growth was expected to be that strong.***

*At the moment the PBOC is using reserve requirements as a form of monetary easing.  However, the main distinction between RR and OMO/LSAP is that the former eases by reducing demand for bank reserves whereas the latter supplies a greater quantity.  As part of a banking system, individuals banks cannot create or eliminate reserve balances with the PBOC therefore it is up to the CB to properly supply the banking system with the quantity demanded.  Otherwise, the PBOC may not be able to credibly target a desired policy rate for very long.

​**It does not seem like the PBOC primarily desires a lower FX rate as this undermines attempts to rebalance the economy away from investment lead growth, property development/speculation, and to a lesser extent (post GFC) export dependence, toward one that is more reliant on domestic consumption.  A declining FX rate reduces household share of income unless domestic unemployment is low enough to cause household income growth to accelerate.

Thus, it's more about steering domestic rates in a way that helps mitigate a slowdown in the domestic nominal economy that threatens to cause rising unemployment and political instability.  This does not necessarily mean that the yuan must weaken materially as long as the PBOC are willing to sell off their dollar reserves while offsetting such sales by buying yuan government bonds.  Eventually, the goal is for the yuan to become a freely floating currency.  Setting policy in a way that guaranteed yuan appreciation was problematic as this promoted excessive private leverage and a carry trade, but this doesn't mean they should set expectations that the yuan can only fall.   If that is the case then what prevents market participants from initiating leveraged short trades against the yuan (in other words leveraged long dollar bets)?  To reduce leveraged bets on the FX rate moving in either direction, volatility must be increased.  The PBOC's large US dollar reserve position enables them to manage the trade in such a way.   

​Moreover, if the PBOC were to allow the domestic monetary base to continue contracting while Chinese nominal and real GDP decelerated, then this strikes me as the worst option available for the global economy.  If they attempt to stabilize/increase the domestic monetary base by engaging in yuan asset purchases that work to reduce domestic rates without managing the potential decline in the FX rate by simultaneously selling dollar assets then this would strike me as the second worse scenario.  ​I do not see how the PBOC can credibly prevent a decline in the yuan over the intermediate or long term if global asset managers expect Chinese economic activity to be much lower in the future.  A deteriorating Chinese economic picture (story) creates the expectation that the PBOC would have to eventually act by easing or that fiscal measures oriented toward the household sector will need to be considered.


***This is not to suggest that I think the Fed will set such expectations anytime soon or sell securities off their balance sheet.  How the Fed manages its big balance sheet using tools such as IOER and ON RRP is the way of the future in terms of monetary policy in the US.  

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