Over the past decade or so, continued purchase of foreign exchange to moderate
the speed of currency appreciation has increased the obligation to sterilize excess
liquidity. Under the inflation targeting regime, excess THB liquidity created by the
purchase of USD needs to be fully sterilized to ensure that short-term money
market rates move in line with the policy rate set by the Monetary Policy Committee (MPC).
Sterilization obligations grew rapidly, especially in 2009–2010 following the Lehman
crisis, increasing by over 50 per cent between end-2008 and end-2010. Nevertheless,
the obligation has stabilized since the second half of 2011, and is in line with a more
balanced capital flow. (Chart 1)