A Federal Call is a special kind of margin call issued by the federal government. (investopedia.com)
I haven't seen any news about increases, but the exchanges must be nervous about traders not being able to meet margin calls given the huge increase in volatility. (ibankcoin.com)
I started getting margin calls which I was able to handle but could have been very bad if I wasn't able to meet the margin requirements. (canadiancapitalist.com)