Chapter 7 of 10 · Specific Trader Profiles and Their Lessons · 2 min read

Bruce Kovner: Position Sizing and Managing Losses Fast

A currency and commodities trader whose interview centers on the specific mechanics of position sizing and rapid loss management.

Bruce Kovner's interview provides some of the book's most concrete, mechanical detail on position sizing — describing a specific approach to determining how large a position should be based on the distance to a predefined stop-loss level, rather than sizing positions by intuition or by a fixed dollar amount regardless of how much room the trade needs to work.

Kovner is also candid about an early, formative large loss caused specifically by ignoring his own risk-sizing discipline on a single trade — a story he describes as directly shaping the much stricter, more mechanical position-sizing rules he applied for the rest of his trading career, connecting directly to this course's earlier point about risk management being the trait every wizard, regardless of method, treated as non-negotiable.

The most important thing I've learned is that you have to lose your fear of being wrong. That's the only way you can get in position to make big money when you're right.

Kovner's position-sizing logic (simplified)

Define the stop-loss level first

The price at which the trade's original thesis is invalidated

Measure the distance from entry to that stop

A wider stop requires a smaller position for the same total dollar risk

Size the position from the fixed dollar risk

Total acceptable loss is decided first; position size is the output, not the input

Result: consistent risk per trade

Every trade risks a similar, controlled amount regardless of how wide its own stop needs to be

Why sizing from the stop, not from intuition, matters

Kovner's specific technique — deciding the acceptable dollar loss first, then deriving position size from the distance to the stop, rather than picking a position size first and hoping the resulting risk is reasonable — inverts the sequence many undisciplined traders actually follow, and produces mechanically consistent risk across trades with very different volatility or setups, directly operationalizing the general "define risk before profit" principle covered earlier in this course.

Key takeaways

Bruce Kovner's interview provides the book's most concrete position-sizing technique: deciding acceptable dollar risk first, then deriving position size from the distance to a predefined stop-loss level.
His own early, formative large loss came specifically from deviating from this discipline — a story he credits with producing the much stricter rules he followed afterward.
This chapter closes out the book's individual trader profiles; the final two chapters synthesize threads (failure patterns, and the book's overall lessons) across all the interviews together.

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