Options Bootcamp
Options 105: Mechanics of the Trade
How do you actually place a trade? We cover Opening vs. Closing transactions, Open Interest, and why "Market Orders" are dangerous in options.
Opening vs. Closing
In stocks, you usually just "Buy" or "Sell". In options, we must be more specific:
1. Buy to Open (BTO): You are buying a contract to create a new long position.
2. Sell to Close (STC): You are selling your existing long contract to exit.
3. Sell to Open (STO): You are selling a contract (writing) to create a new short position.
4. Buy to Close (BTC): You are buying back your short contract to exit.
Open Interest vs. Volume
Volume: How many contracts traded today.
Open Interest (OI): The total number of contracts that are currently "open" (active) in the market. It doesn't differentiate between buyers and sellers.
High OI indicates good liquidity, meaning it is easier to enter or exit a trade without moving the price.
Order Types: The Danger of "Market"
Market Order: "Fill me now at any price." In options, spreads can be wide (e.g., Bid $1.00, Ask $1.50). A market order might fill you at $1.50 when you could have paid $1.25.
Limit Order: "Fill me at $1.25 or better." This is crucial for options trading.
Stop Order: Becomes a market order when a price is hit. Risky in volatile markets.
Stop-Limit: Becomes a limit order when a price is hit. Safer for price control.
Key takeaways
- Know your 4 trade types: BTO, STC, STO, BTC.
- Check Open Interest to ensure liquidity.
- ALWAYS use Limit Orders. Never Market Orders.
- The Bid-Ask spread is a hidden cost; minimize it.
Think you've got it? Take the 5-question quiz
Test what you just learned — a free account shows your score and full explanations.
Series
Options Bootcamp
Keep exploring
More field notes
Jul 4, 2026
What Is Theta? Why Your Option Loses Money Even When You Are Right
The stock did not move all weekend, yet your option lost value — that is Theta, the invisible hourglass over every option buyer. A full walkthrough of time decay.
Jul 4, 2026
What Happens at Options Expiration? One Cent Triggers It, $10,000 Buys the Shares
Doing nothing at expiration is not just "the premium goes to zero": one cent in the money triggers auto-exercise, and a $2 premium can turn into $10,000 of stock. Here is exactly what happens.