> That reminds me of Hong Kong, where I used to live and which maintains a large sovereign wealth fund to ensure its currency is pegged to the US dollar.
That doesn't sound like a soverign wealth fund. Foreign currency reserves are not the same thing as a soverign weath fund.
HK has a currency pegged to the USD via a currency board, that is (similar to a stable coin) backed one-to-one with USD denominated short-dated treasuries. That is within the HK exchange fund operated by the HK Monetary Authority.
The exchange fund also (and somewhat controversially) runs additional portfolios (with foreign shares and bonds, and private equity, real estate etc.) in the manner of a sovereign wealth fund.
That doesn't sound like a soverign wealth fund. Foreign currency reserves are not the same thing as a soverign weath fund.