Are they? Spreads have tightened massively since the advent of HFT which has knock-on effects for the small investor both in terms of cheaper personal trading and lower costs for those managing their retirement/mutual funds (see Vanguard's opinion on HFT[1]).

In terms of resources, Virtu is publicly traded and has a market cap of 6.3bn, Citadel was recently valued at 22bn, the total sector is maybe 100bn. Meanwhile our society ascribes about 260bn of value to Coca Cola alone.

[1] https://www.ft.com/content/ff8c6486-cb37-11e3-ba95-00144feab...

Spreads may have tightened, but payments for order flow suggest to me there's a new flavor of front running involved via HFT and dark pools. But I'm no expert.

How? No offence but it just sounds like conspiratorial nonsense based on some scary sounding terms.

Payment for order flow is an example of the incentives of retail traders, retail brokers and HFT market makers aligning. The market makers are able (and obligated) to improve prices because they have paid to receive flow they are almost certain is not toxic. Meanwhile they charge the likes of hedge funds higher prices as they can't guarantee the reasoning behind their trades (i.e. they may be about to have their faces ripped off).

The HFT firm takes their (tightened) fee for making a market, kicks some back to the retail broker, and because the broker earns money that way, they offer commission-free trading to the retail trader.

The book Flash Boys deals with this. It's a long time since I read it, but IIRC brokers need to split large orders and route them to different exchanges to get the best price (which is required under 'best-effort execution'). These orders will hit the exchanges at different times giving enough time for HFT to observe them at one exchange and front-run them at the other.

> The book Flash Boys

Is a hopelessly bad book. It's a thinly disguised advertisement for IEX.

> front-run

I do not think it means what you think it means.

Most large orders won’t be retail traders though.

> No offence but it just sounds like conspiratorial nonsense based on some scary sounding terms.

It's exactly that.

Are you worried about getting front run for fractions of a cent? I’m not. I’d rather have penny wide spreads instead of 1/8 dollar (or larger) like the old minimum tick size.

Dark pools reduce volatility, it’s just liquidity outside of the normal order book. Regular people don’t need dark pools because they aren’t slinging $500M block trades. Furthermore, trades can happen off-exchange without dark pools.

It sounds like you aren’t even an amateur, let alone an expert, no offense.

> but payments for order flow suggest to me there's a new flavor of front running involved via HFT and dark pools.

I know what those words mean individually. But put together like that they make no sense.

Naw, cable is slow. Even if it's optical. Still slower than direct microwave connection via line-of-sight point-to-point systems.

Anyone doing fiber is doing the wrong technology, if they want to minimize total end-to-end latency.