I don’t think it’s really rigged. The HFT traders do make profits. In effect, they skim a bit, and I think the practical effect of this is to widen the bid-ask spread a bit. The market is still a lot more fair than 30 or 40 years ago when there was a mandatory bid-ask spread quoted in fractions of a dollar, and the brokers pocketed the difference. Now, the brokers and market makers are dealing in penny spreads... and yeah, the HFT guys pick up some... but regular investors are a lot better off than they used to be.
Much more fair then when Joe Kennedy made a fortune kitting stocks.
In effect, they skim a bit, and I think the practical effect of this is to widen the bid-ask spread a bit.
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The penny pricing has NARROWED the spread ,,, the NYSE hated to go to it because it put their people out of business (the market makers that have seats and their traders in the pits) and gave the profits to the huge HFT wirehouses... now there is basically no backstop to an out of control market is a bad trade is entered... say a price wrong by a few decimal points or a LARGE quantity that can’t be realistically filled..