Let's say that your margin requirement tonight is $100,000. You have to have at least $100,000 in your account. Your FCM, has to set aside $8000 of their capital toward a risk deposit. https://www.gpo.gov/fdsys/pkg/CFR-2016-title17-vol1/xml/CFR-2016-title17-vol1-sec1-17.xml Minimum financial requirements for futures commission merchants and introducing brokers.(a)(1)(i) Except as provided in paragraph (a)(2)(i) of this section, each person registered as a futures commission merchant must maintain adjusted net capital equal to or in excess of the greatest ofA) $1,000,000;(B) The futures commission merchant's risk-based capital requirement, computed as eight percent of the total risk margin requirement for positions carried by the futures commission merchant in customer accounts and noncustomer accounts.