At the outset, here are the countries whose Central Banks have zero or negative interest rates,
The Swiss National Bank has around $800 billion in foreign currency investments. Amongst it’s famous holdings are a $3 billion investment in Apple (and it has been buying more shares) and $1.5 billion investment in Facebook. It has recently forecast that it will make a profit of 54 billion Swiss Francs ($55 billion) for the 2017 financial year mainly down to its overseas investments.
The Bank of Japan has a target to buy 6 trillion Yen ($54 billion) worth of exchange traded funds a year. It now holds almost 82% of all ETFs in Japan and is indirectly the largest shareholder in many large Japanese companies.
The European Central Bank invests in corporate bonds amongst other things. It has about 112 billion Euros of corporate bonds and recently is alleged to have lost around 200 million Euros (or 55% of its investment it made via the Finnish Central Bank) in scandal hit Steinhoff.
“A banker is a fellow who lends you his umbrella when the sun is shining, but wants it back the minute it begins to rain.” – Mark Twain