They suppress the price by selling huge numbers of gold futures, and rolling over the contracts on expiry. The size of the futures market is many many times larger than the physical market, hence the gold price is dominated by these paper transactions.
Currently, this does not seem to be a major factor controlling bitcoin pricing.
Recently, I read:
LedgerX LLC has received permission to trade bitcoin futures and options from the Commodities Futures Trading Commission (CFTC). ProShares has filed an application for an ETF dependent upon receipt by the Chicago Board Options Exchange (CBOE) of approval for trading of long and short options on bitcoin. Wall Street sees the demand and wants a piece of the supply.
Does that mean that we can see similar shenanigans, where the price of Bitcoin is totally determined by the Central Banks and financial organisations, rather than by supply and demand from bitcoin users?
What does that mean for Satoshi's dream of independence from central banks?
Am I being unduly pessimistic?