37XuVSEpWW4trkfmvWzegTHQt7BdktSKUs
According to what I read in some reports, it is the richest non-exchange address. I also read that at least one third of these bitcoin has been transferred from Huobi exchanges. As Withdrawing that big amount of bitcoin from Huobi exchange require KYC, so Huobi should know the person behind this transaction.
Assume that the government find this transaction suspicious and want to know the owner of these bitcoins. The government can force Huobi to give them the documents of the owner of this wallet. Huobi can be forced by court if they don't give those documents to government.
Huobi is currently based in Singapore and they have offices in the United States, Korea, Japan and Hong Kong. They have users from all over the world and the nationality of this particular individual may be difficult to establish. Now the Singapore government can't force the exchange to reveal the identity of the user, as he may not be a SG national. On top of that, Singapore is not an authoritarian nation like China to dictate the terms and conditions to cryptocurrency exchanges.
That said, I still have doubts on whether this particular address is being held by an individual or a business firm (such as a cryptocurrency exchange). Individuals are unlikely to hold this much coins in a single wallet. They are likely to split their holdings, in order to avoid the threat from hackers. Normally it is the exchanges who keep this much volume in a single wallet. Lots of people are claiming that this is not an exchange wallet address... but I am still not 100% convinced.