Some thoughts on tightening, quantative and other
Federal Reserve Bank of America
The Congress established the statutory objectives for monetary policy: Maximum employment, stable prices, and moderate long-term interest rates--in the Federal Reserve Act.

The European Central Bank has only one task to keep inflation under 2% but close to 2% The two central banks have also some duties to some parts of the local economy, but at the moment we disregard those auxiliary tasks.

The economic crisis starting in2008 has lead the two banks to decrease the interest rates to close to or under zero % points. To further enhance the economies the banks have started quantative easing which is the term used to describe the central banks purchases of government and some other bonds.
The result of those actions have possibly lead to an improvement in the economy as measured by the growth in GDP.
The central banks started with the lowering of interest rates, as interest rates went down towards zero  first the Fed then the ECB started quantitive easing. The ECB was in the beginning very reluctant to buy government bonds but eventually succumbed and bought bonds massively.
Other central banks followed in essence the same path.
Presently the central banks balance sheets are thick with various bonds of different quality and duration.
The central banks have different accounting principles the Fed has its very own as opposed to the ECB. The ECB and most other central banks use very slight modifications of generally accepted accounting rules (GAAP), which means valuations to market. The Fed values all its physical gold to USD 42/toz and bonds to their respective nominal value with some small exceptions for zero interest bonds.
When interest rates begin to rise the ECB book value of their bonds  will decrease significantly.
This difference in accounting principles makes the ECB reluctant to increase interest rates as it will cause losses in its bond portfolio. When the inflation improves towards 2% and the ECB sees reason to tighten it will sell its bonds to soak up liquidity and thus cool the inflation expectations to remain close to but not above 2%
The Fed on the other hand will keep its bonds to maturity and they increase the fed funds rate to cool off the US economy, the book value of their bond portfolio will remain intact without losses
The resulting strengthening of the USD to the EUR is really of no concern to the Fed if it does not increase US unemployment, which a moderate revaluation of the USD hardly will.
What the Bank of England will do is unpredictable in view of possible brexit and that they cannot even find a domestic governor.
The Riksbank (Sweden) will probably sell bonds and increase the repurchaserate to help the Swedish export industry although its mandate dose nor include exchange rate nor unemployment but they care about both.
Åhus 16-05-20
Kjell Steenberg
Chief economist at the think tank REXUS