Why is Immediacy So Expensive?

In the second half of Chapter 14, Larry Harris gives us the “cheat sheet” for predicting how wide a bid/ask spread will be. If you’re building a trading system or managing a portfolio, these are the variables that determine your “slippage.”

The Three Master Levers

Every spread in every market is controlled by three main factors:

1. Information Asymmetry (The Smart Money Fear)

If a dealer thinks they are trading against someone who knows something important (like an insider), they widen the spread. They are basically building a “moat” around themselves.

• Wider spreads for: Small stocks, young companies, and “growth” industries (where information is scarce and valuable).
• Narrower spreads for: Large firms, mature industries, and well-diversified conglomerates.

2. Volatility (The Risk Premium)

Dealers hate rollercoasters. If a stock is swinging wildly, the dealer is at risk of losing money while they hold their inventory.

• The Timing Option: In a volatile market, your limit order is much more likely to be “picked off” by a fast trader. To compensate, everyone pulls their orders back, making the spread wider.

3. Utilitarian Interest (The Volume Lever)

This is the good stuff. If thousands of regular people (investors, hedgers, gamblers) want to trade, the market becomes very active.

• Economies of Scale: Dealers can spread their fixed costs over more trades.
• Inventory Safety: It’s much easier for a dealer to get rid of a position if there’s a constant stream of buyers and sellers.
• Competition: When a market is active, public traders use limit orders to undercut the dealers, forcing the spread down.

The “On-the-Run” Effect

Harris points out a cool phenomenon in the bond market. When the US Treasury issues a brand new bond, it’s called “On-the-Run.” Everyone wants it, it trades constantly, and the spread is tiny. As the bond gets older (becomes “Seasoned”), people stuff it into their retirement accounts and stop trading it. The volume drops, and the spread widens.

Market Failure: The Tiny Firm Problem

Why don’t your local mom-and-pop burger shops trade on the stock exchange? Market Failure. If a firm is too small, there isn’t enough information for a dealer to feel safe. The spread would have to be so wide (say, 20% of the price) that nobody would ever buy the stock. This is why small businesses have to rely on banks and venture capitalists—private markets where the investors can do “due diligence” and watch the managers closely.

Summary: The Spread is a Signal

A narrow spread is a signal that a market is healthy, transparent, and full of regular people. A wide spread is a warning that you are entering a dangerous zone full of insiders, high risk, and low volume.

Next time, we’ll move into Chapter 15 and meet the Block Traders—the specialists who handle the massive orders that are too big for the regular market.

Next Post: Block Traders: The Heavy Lifters