10s of billions?  That&#x27;s a bit optimistic.  The best HFTs, of which there are a handful, have revenues of roughly $1 billion.  That&#x27;s revenue.  Their net profits are usually in the $10 to $100 million range.  (See for example, Virtu&#x27;s recent IPO filing.)  These are successful global businesses, but they&#x27;re hardly outliers in that crowd.  Hell, Twitter had more revenue last year.