How Is the Opening Price Determined?

Market Rebellion Coach's Corner: Limit Order Books & Opening Rotations - Summary

Key Concepts:

• Limit Order Book (LOB): A system in financial markets where buy and sell orders are listed with specific price limits.
• Market Order: An order to buy or sell immediately at the best available price.
• NBBO (National Best Bid and Offer): The highest bid and lowest offer available across all exchanges.
• Opening Rotation: The process by which options prices are determined when trading begins at 9:30 AM.
• Marginal Pairs: The orders that ultimately determine the opening price by creating the first failed cross.
• Price Priority: Orders are ranked based on price (highest bid, lowest offer).
• Time Priority: When prices are equal, orders are ranked based on the time they were entered.
• Partial Fill: When an order is only filled for a portion of the requested quantity.

1. Introduction & Market Education

The video begins by emphasizing the importance of quality market education for traders of all levels. Market Rebellion offers a comprehensive curriculum covering options trading from beginner to advanced, focusing on practical application and adapting to market shifts. Bill Johnson, Head of Options Education, introduces the topic of limit order books and their role in price determination.

2. Context: Current Market Conditions & Miami Event

The discussion is framed around a particularly cold day in South Florida, and the upcoming Market Rebellion event in Miami (Wednesday-Thursday, airing Thursday at 5:00 PM Eastern). The Coach’s Corner session will cover topics discussed at the event, specifically focusing on limit order books.

3. Limit Order Books: Fundamentals

The core of the discussion revolves around understanding limit order books. A limit order specifies the maximum price a buyer is willing to pay (buy limit) or the minimum price a seller is willing to accept (sell limit). Unlike market orders which execute immediately, limit orders are conditional and may not be filled. All orders entering the book are limit orders, and market makers facilitate trading by matching these orders.

4. How Prices are Determined: The Opening Rotation

The video explains the process of the opening rotation, which occurs when trading begins at 9:30 AM. Options prices aren’t immediately available; they are determined through a process of repricing based on the underlying stock’s opening price. The system starts with at-the-money and near-term options, then progresses to longer-dated options (LEAPS). Historically, this process took up to 10 minutes, done manually with paper orders, but is now nearly instantaneous.

5. The Model & Marginal Pairs

A simplified model is used to illustrate how prices are determined. Orders are stacked based on price priority (highest bid, lowest offer) and then time priority. The key concept is identifying the “marginal pairs” – the orders that, when crossed, determine the opening price. This is the point where supply and demand meet. The video clarifies that the opening price is a single price, not a bid-ask spread, used to clear the market.

6. Real-World Complexity: Unequal Order Sizes

The discussion addresses a question raised by viewers regarding the simplification of assuming equal order sizes. The video demonstrates how the process works with varying order sizes, showing that the opening price is determined by balancing the total number of buyers and sellers at different price levels. The model uses an Excel spreadsheet to illustrate this process, calculating net buys and sells at each price point.

7. The Role of Market Makers & Liquidity

The video emphasizes that prices are determined by the market, not by market makers dictating them. Market makers act as facilitators, balancing supply and demand and providing liquidity. The discussion highlights the significant amount of capital and sophisticated algorithms employed by market makers (e.g., Goldman Sachs, Peak Six) and the competitive nature of the market.

8. NBBO & Level 2 Data

The National Best Bid and Offer (NBBO) is explained as the best available price across all exchanges. Level 2 data provides a view of the order book, showing individual orders and the exchanges they originate from. While Level 2 data was once considered a significant advantage, it’s now widely available and doesn’t guarantee trading success.

9. Partial Fills & Order Execution

The video explains the concept of partial fills, where an order is only executed for a portion of the requested quantity. This can occur when there aren’t enough matching orders at the specified price. It’s emphasized that just because a bid or offer is visible doesn’t guarantee a full fill.

10. Key Takeaways & Event Promotion

The video concludes by reiterating the importance of understanding limit order books and the opening rotation process. It emphasizes that the market is driven by supply and demand, and that market makers facilitate trading rather than controlling prices. The speakers promote the Market Rebellion event in Miami and encourage viewers to access the virtual pass.

Notable Quotes:

• “Knowledge is power and lack of knowledge in what you're doing can be costly. Very costly.” – Bill Johnson
• “Prices are determined by the market, not the market maker.” – Bill Johnson
• “The markets are very very liquid these days. They're very uh computer uh algorithmdriven models that are creating these markets.” – Sue
• “It’s not some clown behind uh you know some post somewhere you know saying oh I’ll sell them at five.” – Sue

Technical Terms:

• LEAPS: Long-term Equity Anticipation Securities – options with expiration dates more than one year out.
• Volatility: A measure of price fluctuations in an asset.
• Algorithmic Trading: Using computer programs to execute trades based on pre-defined instructions.
• Order Flow: The volume of buy and sell orders entering the market.

Synthesis:

This Coach’s Corner session provides a detailed explanation of how options prices are determined, particularly during the opening rotation. It moves beyond basic options theory to explore the mechanics of limit order books, the role of market makers, and the complexities of real-world trading. The video emphasizes the importance of understanding these underlying processes for successful options trading and highlights the resources available through Market Rebellion’s educational programs.