In order to draw more Market Depth from users, CoinEx provides Maker with incentives. Negative fees mean incentives. The details are as follows.
Maker：Market makers are those who are willing to buy or sell at a certain price. They provide the gasoline/depth for the market.
Taker：Market takers are those who actively look for a suitable published proposed buy/sell trade and accept it. They step on the pedal so that the gasoline is used up.
The aim of maker-taker mechanism is to stimulate trading activity within an exchange and keep price stabilized.