Kraken is a US-based cryptocurrency exchange and one of the largest bitcoin exchanges in terms of volume and liquidity.
It provides Bitcoin pricing to the Bloomberg Terminal and has considerable influence on the overall crypto market. Kraken offers a number fiat funding and transfer options.
There are 18 BTC pairs and 16 USD pair to trade
Fees vary depending on the volume - for main trading pairs this is between 0.1-0.35% - however for other less common crypto pairs the range can be as low as 0.05% or as high as 0.75%. There are also 0% fees for some trades.
Withdrawals and deposits are variable depending on the method - although in general all fees are 0.19% with a $20 minimum.

GBX is developing a token sale platform and digital asset exchange that is designed to make traditional investors more comfortable with investing in cryptocurrencies. The Gibraltar Blockchain Exchange (GBX) is a subsidiary of the Gibraltar Stock Exchange (GSX). They hope to use their position as a regulated European exchange in Gibraltar to position themselves as a reputable option for investing in digital assets. GBX issued an Ethereum-based token called Rock (RKT).