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Wall Street’s ‘Private Rooms’

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Re: Wall Street’s ‘Private Rooms’

#211
post #139

Earlier quoted context omitted.

That is irrational. It suggests every time someone sees a market price at $5 they could put in an enormous fake sell order for shares at $5.05 to buy shares at $4.90 then cancel the fake order, which makes no sense. "The market" is giving away freebies in an insane way. If the clearing price is $5 and someone puts in a huge sell order for $5.05 there is no reason for the clearing price to drop.

>If the clearing price is $5 and someone puts in a huge sell order for $5.05 there is no reason for the clearing price to drop. Except that the market is all game theory. If someone who bought a million shares with an ideal exit of $5.10 sees 5 million shares for sell at $5.05 it can absolutely inspire them to sell cheaper because the idea is predicting directional movements. I design some financial software and the…

> If someone who bought a million shares with an ideal exit of $5.10 sees 5 million shares for sell at $5.05 it can absolutely inspire them to sell cheaper because the idea is predicting directional movements.

Your basic argument there seems is "new information can cause the price to move at random". And I accept that. But it doesn't matter to anyone on the lit market because the trades on the dark market would help or hinder them at random if they were publicised. If there isn't a systemic bias then it is just noise, I have a choice between the price on the lit market or ... the price on the lit market plus some random variable that might be positive or negative. It doesn't change how much money I expect to make. I'm not at any sort of disadvantage.

It doesn't change my ability to value my trades and it doesn't cause me to think I'm going to be better or worse off. We already know that distinct market participants have different knowledge and world models. There isn't anything here that it is useful to adjust.

> Think of it as a maze and every stock and price point combination is a doorway.

This explanation literally makes no sense to me; I don't see how it matters. Someone offers to buy at $X/sell at $Y. Someone else chooses to take the other side of the trade or not. It is only that weirdly complex if you want it to be.

If you need omniscient knowledge of the market structure to value a good then it isn't possible to trade it because your knowledge is always lacking information that is relevant to valuations. For example, you can't know about orders that are about to be lodged in the immediate future. We all have to operate with the understanding that some other market participants know things we don't and value things differently. It doesn't make the trading environment unfair.

You seem to have a traders perspective here where you want to turn a turn an asymmetry of nearly irrelevant information into profit. I'm cool with that, but I don't care if it works or not. It sounds like a zero-sum game, someone is going to lose. and I don't see why I should be phased about who or why. I just want the market to offer to buy/sell things at a fair price. Dark pools don't seem to influence that in any way, the incentives mean that the price signalling should be basically honest.

Re: Wall Street’s ‘Private Rooms’

#212
post #145

Earlier quoted context omitted.

Although the above example was missing some details, I suspected it was meant to illustrate the following effect: The public last price was $5, so bid/ask will be around that price let's say 4.99/5.01, if you buy with a market order you'd pay approximately $5 ($5.01). But if there is a new large sell order for 5 million shares at 5.05, then the market would react to this information and adjust bids & asks. For illust…

Why would lots of shares available at 5.05 cause others to sell shares for 4.90?

Because you want to move ahead of the 5.05 seller and be sure your shares can sell for $4.90. If the $5.05 seller is trying to sell 5 million, but it's taking a long time. They might drop down to $4.85 or something. It's all game theory and predicting what others will do. A big part of that is having all of the information.

Re: Wall Street’s ‘Private Rooms’

#213

Earlier quoted context omitted.

If you look up RegNMS the goal is to make public markets fair by having rules that have to be met in order to trade. Dark pools allow participants to 'hide' information that's not public. It is mostly about the order books. If dark pool sell order for 1B of TSLA stock goes on the order book, only other members of the pool get that information. The dark pools are required to still follow RegNMS rules for trade prices,…

> In your neighbor's house example, it would be like if there was a street market auction for trading cards happening in your neighbor's front yard, but in the house your neighbor and another neighbor had gotten together to trade 100x the average #of cards using the prices they hear from outside, and the people outside only see the deal they made after it's done. Isn't that how everything is traded? Am I supposed to…

For these institutional traders, the pools offer them opportunities to trade with a small set of counter parties that also have deep deep liquidity, so in a sense it is kind of like the wholesale markets for retail. Orders hit the book in the pool and they don't have to worry about 'current retail' stock and can trade massive blocks with trade certainty.
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