Who pays for the RFQ fee and how is the RFQ fee calculated?

If you respond to an RFQ by submitting an ask and got accepted, you will pay for the RFQ fee based on your trading volume in the past 30 days. No fees will occur if your ask does not get accepted.

The RFQ fees have a tiered system based on the trading volume:

[Volume $, RFQ fee rate %]