At present, the G7 has basically focused its work on the regulation of encrypted digital currencies and has not considered the potential of digging for digital assets. So basically you can not find bitcoin, ethernet or zcash, the cryptocurrencies, on the central bank's investment vehicles and currencies.
However, the situation will be different in 2018 as the G-7 central banks will start buying encrypted digital currencies to strengthen their foreign exchange reserves.
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https://bitzamp.com/g7-central-banks-to-start-buying-bitcoin-and-other-cryptocurrencies/