It is collated by the CFTC from submissions from traders in the market and covers positions in futures on grains, cattle, financial instruments, metals, petroleum and other commodities.
[2] The weekly report details trader positions in most of the futures contract markets in the United States.
Data for the report is required by the CFTC from traders in markets that have 20 or more traders holding positions large enough to meet the reporting level established by the CFTC for each of those markets.1 These data are gathered from schedules electronically submitted each week to the CFTC by market participants listing their position in any market for which they meet the reporting criteria.
Thus, as a general rule, more than half the open interest in most of these markets is held by commercial traders.
Another theory is that commercial traders understand their market the best and taking their position has a better chance of profit (which is pretty much the same thing as the "small speculators" being wrong).