They may be manipulating every single market that is relatively illiquid compared to stocks and rates. And they may have taken exposure to bitcoin, although i highly doubt it, but probably only via futures, not actual bitcoins. They have to justify exposure to bitcoin futures to shareholders and regulators. And they have to justify exposure to actual bitcoins. In the absence of regulation, goldman buying 440k bitcoin at 5600 is plain fart and therefore no case of any market manipulation through it. There are plenty of other institutions that can manipulate bitcoin market, not goldman as things stand currently. If the US regulators wont drag them to court or fine them, shareholders will sue them or european regulators will fine them. They are not buying any bitcoin without it being regulated. There is no way to account for that purchase. Its not a fixed asset, its not an intangible asset, it has to be on their balance sheet somewhere. Goldman is a regulated listed financial entity mate!