[teod]

Couldn't find too much information on this, but I see that [https://support.gdax.com/customer/portal/articles/2436336] under "Is GDAX's ether hot wallet insured?" states "The majority of ether and bitcoin deposited to GDAX is held in highly secure cold storage." (GDAX is Coinbase's exchange platform) See also [https://www.coinbase.com/security].