The balance sheets of central banks have massively expanded since the Global Financial Crisis in an attempt to help stimulate demand.
Between 2008-2015 the Fed’s balance sheet grew from $858 billion to $4.3 trillion. Relative to the US economy, this was a massive expansion from 6% of GDP to 25.4% of GDP. Similarly the Bank of England’s (BoE) balance sheet grew from 5.9% of GDP to 22.5% of GDP. However the biggest expansion was in Japan – where the balance sheet grew from 22.1% of GDP pre-crisis to 30% of GDP mid-2012, and then exploded to 65.4% of GDP in 2015 in the Abenomics climate. It is now a huge 320441.8 billion JPY.