The Small Account Problem

Week 1 · Why limited capital changes execution, drawdown and survival before strategy even begins

Course lens

How can a small retail trading account survive execution friction, drawdowns, leverage, and increasingly complex instruments?

The question this week answers

What changes when the account is small enough that every spread, sizing decision, drawdown and forced exit materially reduces the room to keep trading?

The point is not to find a “best” trading style or instrument. It is to understand what can make the account fail.

By the end of this lecture

  1. describe a market as a matching mechanism, not an oracle
  2. explain why account size changes the importance of fixed frictions and drawdowns
  3. connect whole-share sizing and leftover cash to capital efficiency
  4. preview how each later instrument adds a new survival risk

Why “small account” is its own problem

Execution friction

Spread, fees and slippage consume a larger share of small expected gains.

Drawdown asymmetry

Losses shrink the capital base; recovery requires a disproportionately larger gain.

Sizing constraints

Whole shares, contract sizes and minimum margins create unused cash or oversized positions.

Forced exits

Leverage can close a position before the market view has time to recover.

The first objective is not maximising return — it is preserving enough capital to remain able to act

A market still just matches buyers and sellers

A market is any standing way for buyers and sellers to meet and agree on a price — a stock exchange, a futures or options venue, a crypto app. None of them guarantee a “correct” price; each only produces the price the last willing buyer and seller agreed to.

Seller

Simulated “Northbank Traders” — will sell for $37.50

Buyer

Will pay up to $37.80

Match

Buyer accepts $37.50 — that is now “the market price”

Simulated prices. Nothing about that match says whether $37.50 is “good value” — only that two sides agreed.

Whole-share constraints show up immediately

$1,000 budget ÷ $37.50 a share = 26.67 shares



Shares trade in whole units → 26 shares



26 × $37.50 = $975.00 spent



$1,000 − $975.00 = $25.00 left over, uninvested

That leftover cash is small here. Later weeks show how contract sizes and margin can make sizing constraints much larger.

One progression, five different survival pressures

The semester still moves through stocks, margin, futures, options and crypto — each is now a case study in a different failure mechanism. The instrument changes; the course keeps asking the same question: how much room does the account have before friction, loss or forced closure takes control?

Stocks · Weeks 2-7

Execution friction

Margin · Week 8

Forced exit

Futures · Week 9

Embedded leverage

Options · Week 10

Nonlinearity

Crypto · Week 11

Extreme leverage

Try it yourself

Calculate

Pick a simulated share price between $10 and $200, and a simulated budget between $200 and $2,000.

Work out: how many whole shares that budget buys, the total cost, the leftover cash, and the percentage of the budget that remains idle.

The takeaway

  1. A market sets a matched price; it does not protect a trader from bad sizing or execution.
  2. Small accounts feel frictions and drawdowns more quickly because there is less capital buffer.
  3. The course now follows one question across every instrument: what reduces the account’s ability to survive?
  4. Stocks are the baseline; later weeks add leverage, contract obligations, nonlinear payoffs and liquidation risk.

Next week

Week 2 — execution friction: exchanges, brokers, bid/ask spreads and order types.