I am exploring how much leverage day trading firms are able to take with their capital base. I assume that stocks would be different from futures and other instruments but that everybody is at some point tied to the same economic consideration - margin. Are prop firms restricted to a fraction of margin, multiples of margin? Anybody know how this works from the firm side? An example would be that CTA's might stick with 25% margin to equity but for daytrading why not lever up more, even much more?