August 8, 2018

Rules and Money

There are two pillars to market intelligence: The Rules, and The Money.

By market intelligence, I mean information about what’s pricing a stock. So, translating, information about what’s pricing a stock must derive from the rules that govern stock-trading, and how money conforms to those rules.

Wouldn’t that be supply and demand?  Would that it were! There are instead four big rules for stocks now, tenets of Regulation National Market System about which every investor and investor-relations officer should have a basic grasp.

“Quast,” you say. “This sounds about as exciting as cleaning a tennis court with a tooth brush. In Houston. In the summer.”

It can be very exciting, but the point isn’t excitement.  If you don’t know the rules (always expect your market intelligence provider to know the rules for stocks), your conclusions will be wrong.  You’ll be guessing.

For instance, if you report strong results and your stock jumps on a series of rapid trades, can a human being do that?  Refer to the rules. What do they require?  That all marketable trades – an order to buy or sell stock – be automated.

No manual stock order can be marketable. Manual orders are nonmarketable, meaning prices for the stock must come to them instead. Picture a block of cheese and a grater passing by it and shaving some off.

The rule creating this reality in stocks is the Order Protection Rule, or the Trade-Through Rule. Same thing. It says traders cannot trade at $21.00 if the same stock is available for $20.99 somewhere else. To ensure compliance, regulators have mandated that orders wanting to be the best bid to buy or offer to sell must be automated.

And the bid to buy will always be lower than the offer to sell. Stocks may only trade at them, or between them.  There can only be one best price (though it may exist in several places).

Now start thinking about what money will do in response.  Orders will be broken into pieces. Sure enough, trade size has come down by factors, and block trades (we wrote about it) are a tiny part of the market.

Big Commandment #2 for stocks is the Access Rule. It goes hand-in-glove with the first rule because it’s really what turned the stock market into a data network.

The Access Rule says all market centers including stock markets like the five platforms operated by the NYSE, the three owned by the Nasdaq, the four owned by CBOE, the newest entrant IEX, and the 32 broker markets that match stock trades must be connected so they can fluidly share prices and customers.

It also capped what exchanges could charge for trades at $0.30/100 shares – paid by brokers trading in the stock market for themselves or customers (the SEC Fee Pilot Program aims to examine if these fees, and their inverse, incentive payments, cause brokers to execute trades in ways they would not otherwise choose).

The third big rule outlaws Sub-Penny Pricing, or quoting in increments so small they add no economic value.  You may still see your stock trading at $21.9999 because of certain exceptions for matching at midpoints of quotes.

Reg NMS lastly imposed new Market Data Rules. Since everyone is sharing prices and customers on this network called the stock market, plans had to be refined for pooling data-revenue (prohibiting sub-penny trading was meant to prevent a proliferation of tiny meaningless prices).

Yet, data is a byproduct of prices. There are hundreds of millions of dollars of revenue governed by the Consolidated Tape Association, which divides proceeds according to how various platforms and brokers quote and trade in accordance with best prices. Outside the CTA, there may be billions of dollars now in proprietary data feeds.

These rules drive how money behaves. The fastest machines will price your stock to start the day no matter where you trade, because they have the quickest bids and offers. But their purpose is to profit on changing prices, not to own stocks.

Passive investment dominating the market is aided by rules. What lies between the bid and the offer? The average price. Those tracking benchmarks like index mutual and exchanged-traded funds get a boost toward their objective.  Prices become uniform (our data show very tight Poisson distribution in the stock market – which helps securities tracking benchmarks).

And because stock prices are highly unstable – average intraday spread in the Russell 1000 the past five trading days is 2.6%, and the typical stock trades over 16,000 times daily in 167-share increments – investors turn to substitutes like derivatives. Even Warren Buffett who once famously skewered them as instruments of mass financial destruction has large derivatives positions.

Let’s finish where we started. Why doesn’t supply and demand drive stock prices? Because rules governing trades don’t let supply and demand manifest naturally. The greatest proportion of trades are now driven by machines wanting to own nothing, the opposite of a market animated by supply and demand.

When you look at your stock or stocks in your portfolio, remind yourself: What’s driving them up and down are rules, and money racing around a course in compliance with those rules.  Some part is rational. A bunch of it isn’t.  We all – investors and public companies – can and should know what’s going on. The first rule, after all, is to be informed.

Welcome to the 21st century stock market.

Share this article:
Facebook
Twitter
LinkedIn

More posts

dreamstime l 779123
January 14, 2026

Should the Federal Reserve be independent?  Depending on how you count, the enumerated powers of the United States government in Article I Section 8 of...

dreamstime l 165518220
January 7, 2026

If we need more proof that the stock market is an autonomous system, look no further than a rally on the “Donroe Doctrine,” as some...

dreamstime l 153419812
December 17, 2025

The market isn’t really the market. Yesterday, I told Diane King Hall on Schwab Network that futures are no crystal ball. Cracked myself up with...

dreamstime l 7462204
December 10, 2025

I don’t know if it’s better to be the Wildebeest or the Hyena. But there’s safety in the herd. That’s one conclusion from my NIRI...

dreamstime l 62060641
December 3, 2025

Where is the money coming from? It’s the question Karen and I had down in Cabo ahead of Thanksgiving as we observed the hillsides overlooking...

dreamstime l 159387318 (1)
November 26, 2025

We bid November 2025 goodbye and we say hello to a tryptophan high (yes, that rhymes on purpose). You EDGE subscribers, our next live Discussion...