The Trade Where I Discovered I Had No Idea What My Maximum Loss Was
I had been invested for about eighteen months when I bought a position and did not calculate the maximum loss in advance. The stock looked right. The setup was clean. I bought a round number — 100 shares at $47 — because 100 shares felt like a sensible, organised amount to own.
Three weeks later the position was at $39. I had a vague mental stop somewhere around $42 that I had never formalised, had moved twice as the position declined, and had ultimately abandoned because the stock had gone below it without my acting on it. The position was now down $800 on a $4,700 initial investment — a 17% loss. My account at the time was approximately $22,000. That $800 loss was 3.6% of the account — more than I had intended to risk on any single trade, but I had never calculated what I intended to risk because I had not approached the entry with a maximum loss calculation.
The problem had not been the stock. The setup had genuinely been correct — the stock recovered and went on to advance 28% from my entry price over the following six weeks. The problem had been the entry process. I had bought a number of shares based on a comfortable-feeling round number, without ever determining what the maximum loss on the trade was or where the stop that enforced that maximum was located. The stop I eventually used was arbitrary. The loss it produced was larger than anything I would have accepted if I had calculated it in advance.
The Three-Number Calculation — Run It Before Every Entry
Decide — before looking at any specific trade — what percentage of the total account value you are willing to lose on a single position. This number does not change based on how much you like the trade. It is a structural rule applied consistently across all trades regardless of conviction level. A typical range is 0.5% to 2% of total account value per trade. At 1%, a $25,000 account has a maximum acceptable loss of $250 per trade. At 2%, it is $500. This number is the budget for the trade's downside. Everything that follows is calculated to stay within it.
The stop is placed just below the Support Level of the base — the structural lower boundary of the consolidation from which the stock broke out. The risk per share is the entry price minus the stop price. If the entry is $79 and the stop is $67, the risk per share is $12. This number is structural — it comes from the chart, not from the investor's preference about how far the stock is allowed to fall. A wide stop means the setup has a larger risk per share. The position size will be smaller to compensate, keeping the total dollar loss within the maximum acceptable loss budget.
Maximum acceptable loss divided by risk per share equals the number of shares to buy. If the maximum acceptable loss is $250 and the risk per share is $12, the position size is 250 divided by 12, which equals approximately 20 shares. Twenty shares at $79 per share means a total position value of $1,580. If the stop at $67 is triggered, the loss is 20 shares times $12, which equals $240 — within the $250 maximum. The position size is not a round number chosen for comfort. It is a specific calculation derived from the risk budget and the structural stop placement.
A building contractor preparing a renovation quotation does not start by choosing what materials they want to use and then hoping the cost fits the client's budget. They start with the client's budget — the maximum the client is willing to spend — and then select the materials and scope of work that deliver the best possible result within that constraint. The budget is the starting point. Everything else is derived from it. Position sizing works identically. The maximum acceptable loss is the budget. The entry price and stop price determine the risk per share — the cost per unit of the trade. The position size is how many units the budget can afford. Starting with a comfortable-feeling share count and hoping the loss stays manageable is the equivalent of the contractor choosing materials first and sending an invoice that may or may not fit the client's budget. The calculation goes in the opposite direction: budget first, then everything else.
Same stock, same entry price, same setup. The round-number approach produces an unknown maximum loss. The calculation approach defines the maximum loss before the first dollar is committed — and the position size follows from that definition automatically. For illustrative purposes only.
The question is never how many shares feels right. The question is how many shares keeps the maximum possible loss within the budget. The answer to the second question determines the position size. Every time. Without exception.
What Happens When the Calculation Produces an Uncomfortably Small Position
Sometimes the calculation produces a position size that feels too small to bother with. The entry is $84, the stop is $71 — a wide $13 risk per share — and the maximum acceptable loss of $300 produces a position of only 23 shares worth $1,932. That is 6.4% of a $30,000 account. It does not feel like a meaningful position.
The correct response to this outcome is not to widen the maximum acceptable loss to produce a bigger position. The correct response is to recognise that the setup has a wide stop — meaning the structural risk between the Breakout Level and the Support Level is large — and either accept the appropriately small position or decline to take the trade because the risk-to-reward ratio does not meet the minimum threshold.
A wide stop is structural information. It means the distance between where the entry is and where the thesis is wrong is large. That distance, by itself, is not a disqualifying condition — some setups have wider bases and therefore wider stops — but it determines the position size through the calculation, not through the investor's comfort with a larger dollar amount. Past performance does not guarantee future results.
→ How to Assess Risk and Reward Before Entering a Trade
→ Why Cutting Losses Early Is More Profitable
→ The Full Position Sizing Framework
Every Friday — Position Size Calculated Before Any Stock Is Published.
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Send Me the Friday FlashFrequently Asked Questions
The standard range is 0.5% to 2% of total account value per trade. The specific percentage depends on the investor's conviction band system and the number of simultaneous positions being held. An investor holding a maximum of five positions who uses a 2% maximum loss per trade has a theoretical maximum simultaneous drawdown of 10% — which is manageable without requiring significant portfolio recovery before resuming activity. An investor holding eight to ten positions at 2% each has a theoretical maximum drawdown of 16% to 20%, which begins to approach uncomfortable territory. The practical guideline: multiply the maximum acceptable loss percentage by the maximum number of simultaneous positions. If the result exceeds 15%, reduce the per-trade percentage. Past performance does not guarantee future results.
No. The stop is placed at the structurally determined level — just below the Support Level — before entry. It does not move down because the position is losing. Moving the stop down to avoid being stopped out converts a pre-defined maximum loss into an undefined one — exactly the situation the calculation was designed to prevent. If the stock declines to the stop level, the stop is triggered and the position is exited. The maximum acceptable loss is realised. The capital is available for the next qualified trade. The stop is not a suggestion. It is the mechanism that enforces the maximum loss calculation.
Yes. Stocks in the Highest Conviction band qualify for full position sizing — the maximum acceptable loss percentage is applied at its full value. Stocks in the High Conviction band qualify for 70% of the full maximum acceptable loss. Stocks scoring in the Watchlist Only band are not entered. This means the same calculation runs for every entry, but the maximum acceptable loss input changes based on the conviction band of the individual setup. A Highest Conviction entry on a $30,000 account with a 1.5% maximum loss has a $450 loss budget. The same account entering a High Conviction setup at 70% has a $315 loss budget. The rest of the calculation proceeds identically from whichever budget applies.
100 shares at $47 because it felt like a round, comfortable number. No calculation. No defined maximum loss. A vague mental stop that moved twice and then was ignored. The actual loss ended up at $800 — 3.6% of a $22,000 account. More than I would have accepted if I had calculated it in advance.
The irony was that the stock was right. It recovered and advanced 28% from my entry price over the following six weeks. The analysis had been correct. The position sizing had not been — and the sizing error had produced a loss from a correct analysis, because I had exited at the wrong price for the wrong reason with no defined framework to tell me otherwise.
The three-number calculation takes ninety seconds. It produces a specific position size that is derived from the risk budget, not from a round number preference. The maximum loss is known before the first dollar is committed. That knowledge changes the whole psychology of managing the position afterward.
Amateurs decide how many shares to buy and hope the loss stays manageable. The process-driven investor decides what they can afford to lose, calculates how many shares that budget allows, and places the trade knowing exactly what the worst-case outcome is before it begins.Every Friday — Stop Level Included. Maximum Loss Calculable Before Entry.
The Friday Report includes the Support Level — the structural stop reference — on every published stock. Five stocks. Every Friday.
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