[gd1]

>So if I offer a trade, and then withdraw the trade because I decide I don't like the idea anymore (or 'any other reason')... that's legal. And routine to do on microsecond timescales.

Yes that's right. So quickly you may as well assume that they are updating the price they are willing to buy/sell continuously in realtime. Which is the idea. And because they are updating their prices continuously and accurately, they can keep the gap between those two prices as small as possible. For some bizarre reason, this is the only field in all of technology where HN contributors get freaked out by this. Name a control system that doesn't update its outputs frequently.

>But offering a trade, and then withdrawing the trade manually a few seconds later because I never intended to execute the trade... that's not legal?

Yes that's right. Markets work on trust, if you don't actually want to buy/sell what you're claiming you want to buy/sell then you are lying. More importantly, if you don't want to trade, what are you doing putting the order in? What does that leave as your motivation? Manipulation, that's what. Which is illegal. It's very hard to define market manipulation, but that's just about the easiest way I can think of - can you think of a simpler definition? They have to settle on some way of describing it, and it's not unusual for crimes to be defined by intent.

>Doesn't HTF presuppose that we are hard-coding this behavior, this tactic, into the trading algorithms of automated traders?

I don't follow

[FireBeyond]

"Markets work on trust, if you don't actually want to buy/sell what you're claiming you want to buy/sell then you are lying."

No, that's patently not true. If you are UNWILLING, or UNABLE, to execute a trade when matched, then you are lying.

Plenty of people "don't actually want" to buy/sell, every day - using that phrasing, you could point to people who are forced to cover shorts or dump a stock as it plummets to recoup some of their losses.

"I don't want to sell this stock at this price, but I WILL" should never be considered fraud - for the very least reason that it opens a deep rabbit hole into a form of thought crime that really, do many market participants want opened - when they're asked to explain, with a straight face and credulity, what their market strategies are really intended to do.

[gd1]

You seem to be mixing up different levels of wanting and intention. I may not want to eat my brussel sprouts for dinner, but when I poke them with a fork and raise them towards my mouth I am intending to eat them. Not pull them away at the last second. I'm sure no one enjoys dumping a stock as it plummets, or wants to dump a stock when it plummets, but when they are actually carrying out the process of selling that stock, then they do want the trade to go through. It is their intention to successfully complete the sale of the stock. That's what we're referring to.

[kasey_junk]

> "I don't want to sell this stock at this price, but I WILL" should never be considered fraud

A) it isn't fraud, it is order spoofing, which is precisely defined to be based on intention.

B) lots of our legal system is based on intention. It is a common aspect, not a rabbit hole.

[mapt]

Every single trade is market manipulation. Actions have effects, regardless of intent.