Personal Finance (25): Is Your Trading System Really Good Enough To Trade Full-Time? (2/3)

Advertising presents full-time trading as a natural replacement for a job: quit the office, free from traffic jams, trade from anywhere, be free by Friday, and the list goes on.

In a bull market the pitch is convincing: when almost everything is rising, almost everyone looks like a genius. Then the market changes. And the large majority of those who took that path fail badly.

This article works through the arithmetic behind the sales pitch, in two steps.

Step one was established in Part 1 (the last article). Professional fund managers — full-time, credentialed, with research teams and direct market access — rarely beat a simple S&P 500 index fund over ten to twenty years. Across fifteen years, roughly nine out of ten active US large-cap funds underperformed it. If that is the record of full-time professionals, the promise made to a beginner deserves real skepticism.

Step two is this article’s subject. Suppose you are the exception, and genuinely hold something better: a long-only system returning 16% a year, with a 25% maximum drawdown and no leverage. Better than the index; better than most professional funds ever achieve. Surely that is enough to quit?

Given a genuinely good system, what capital — and what conditions — must actually be in place before you can live from it?

The intuitive answer is to divide the income you need by 16%. In the stress test that follows, the honest answer is three to four times larger.

That gap is not a technicality. A system’s average return tells you how wealthy you might eventually become; its drawdown decides whether you survive long enough to find out.

None of this is an argument against trading. It is an argument against quitting before the numbers support it.

0.  Setting Up the Exercise

This exercise answers a concrete question: with a genuinely good long-only system (16% CAGR, 25% max drawdown), how much money does an ordinary senior engineer need before he can responsibly stop working — and how many years of saving does it take to get there, starting from nothing?

All figures are rounded, US-based, and built on the assumptions below. They are illustrative, not advice; change any input and the answer changes. This version corrects an important omission flagged in review: a salaried job pays far more than its cash salary once employer benefits are counted — and quitting means self-funding all of them.

0.1  A critical caveat on “long-only, 25% drawdown”

The whole model assumes the system’s worst loss is 25%. For a long-only system that only holds true if it has a trend or cash-conversion filter that moves it to cash when the broad market breaks down. Without such a rule, a long-only system in a secular bear market (2000–03, 2008, or 1973–74) does not politely stop at −25% — it can draw down far deeper and stay there for years, because it has no way to profit from or side-step the decline. Every number in this paper depends on that filter working. A “16% / 25%” system with no exit to cash is a different, more dangerous animal than the one modelled here.

1.  Scenario 1 — Quit Now, Trade Full-Time

The question: what lump sum lets him quit today and live off the system, keeping the same standard of living — including the benefits he used to get for free?

1.1  The naive answer (and why it’s a trap)

His real cost to replace is ~$105,900 (take-home + self-funded benefits). To net that after ~28% short-term tax, he must earn about $147,000 gross in trading profit. The tempting math is:

$147,000 ÷ 16% = $919,000.

This is dangerously wrong. It assumes he earns exactly 16% every single year. He won’t — and the years he doesn’t are the years he still has to eat and pay for his own insurance.

1.2  The stress test that breaks the naive number

Run the exact worst case: he quits, immediately hits the 25% drawdown, and the market goes flat for 3 years while he keeps withdrawing $147k/year to live.

Fig. 1 — Same shock, three starting capitals (benefits-adjusted). At $0.92M the account is gutted with no job to return to; at ~$2.94M it endures.

1.3  The honest answer

The Most Dangerous Moment

The riskiest point is not when someone has no experience. It is when they have just enough success to feel certain.

It usually unfolds in five stages.

Stage 1 — A bull market. They start trading, and the account performs well. Almost everything is rising, so almost everyone looks skilled.

Stage 2 — Confidence. The thought arrives: “Why am I working for someone else when I can make more than my salary doing this?”

Stage 3 — The salary becomes the enemy. The job stops looking like the thing financing the experiment and starts looking like the obstacle to it.

Stage 4 — Resignation. They quit — usually near the top of their confidence, which tends to coincide with the top of the market.

Stage 5 — Trading changes character. This is the critical shift.

Before quitting, the question was: “Let’s see what my system can do.” After quitting, it becomes: “This month’s trading has to pay my bills.”

Those are two entirely different psychological and financial situations — and the system does not know which one it is in.

Example: A Profit Table with CAGR  ≈ 17.3%.MaxDD ≈ -24%. and Sharpe ≈ 1.11 (annualized, Rf = 0)

Note that CAGR is an average number, no a promise of monthly Nor yearly fixed income.  Take for example, if the person after winning consecutively for a few years, and trade full time,... What happen if he chose to start from 2008?  Can he last till 2012?

2.  Scenarios 2 — Keep the Job, Drip-Feed the System

This is the realistic path, and the good news. Running a finished weekly-rebalanced system takes little daily time — easily compatible with a full-time job. (Developing and validating a robust system is another matter entirely, and Part 3 is devoted to it.) So instead of quitting, he keeps his salary and its benefits, invests a fixed slice of his net take-home into the system every year, and lets it compound at 16% until it reaches the ~$2.94M “quit” milestone. Then he can leave — and, if he likes, travel the world while the system runs from a laptop.

To keep it simple and conservative, we assume no salary increases ever (real raises would speed everything up), and that contributions are made once a year and compound at the system’s 16%. Because he keeps his job, his benefits are still covered while he accumulates — another reason the drip-feed path is so much safer than quitting.

2.1  How many years until he can quit?

Fig. 2 — Capital growth by savings rate. The dashed line is the ~$2.94M quit milestone (benefits-adjusted); where each curve crosses it is his freedom date.

3.  How Sensitive Is This to the 16% Assumption?

Everything above rests on the system truly delivering 16% over the long run. If it delivers less — as most do, once real costs and worse years are included — the timeline stretches. Here is the 20%-of-net case at different CAGRs:

4.  The Full Picture — Side by Side

The three lessons

1.  Count the hidden salary. A job pays ~$25k/yr of benefits on top of the paycheck. Quitting means self-funding all of it — which is why the honest capital number is ~$3.4M, not the ~$2.4M you get if you ignore benefits, and far more than the naive $920k.

2.  Drawdown, not average return, sets the capital. A 16% CAGR looks like it needs under $1M; surviving its 25% drawdown plus a multi-year flat market with no salary and no benefits needs ~$3M. The gap is sequence-of-returns risk plus the hidden salary.

3.  Keeping the job while building the trading system preserves an option that quitting removes. Because the system runs in under an hour a day, there is almost no reason to quit early. Drip-feeding turns a terrifying ~$3M lump-sum problem into a patient 18–28 year compounding problem — with a salary AND benefits as your safety net the whole way.

4.  Lower the target, not the caution. Wanting less income in retirement shortens the road far more safely than reaching for more leverage or a higher assumed return ever could.

5.  Does a Bigger Salary Make It Easier? (The Surprising Answer)

Everything so far used a $110k engineer. Intuition says a senior manager on $250k or a director on $500k should find it far easier to quit and trade — they earn so much more. The maths says the opposite. Earning more makes quitting harder, not easier.

The reason is simple once you see it: “same living standard” means replacing a bigger lifestyle. The capital required scales directly with spending, and higher earners are taxed harder on both sides. So the freedom number explodes.

5.1  The capital needed explodes with income

Fig. 3 — The honest capital-to-quit rises steeply with income. A director needs roughly $11.5M — over 3× the engineer — to replace his after-tax lifestyle plus benefits.

5.2  …but the years-to-quit barely move

Here is the genuinely surprising part. Although the director needs over three times the capital of the engineer, if each saves the same percentage of their net income, they reach their (very different) targets in almost exactly the same number of years:

Fig. 4 — The inversion: the capital bars triple, but the gold “years-to-quit” line stays flat. Time to freedom is set by your savings RATE, not your salary.

5.3  So why is it “harder” for high earners?

The timeline is the same only if the high earner actually saves the same percentage — and that is exactly where it breaks down in real life:

•    Lifestyle inflation. The $500k director rarely saves 20% — the bigger house, cars, schools and holidays absorb the extra income, so his effective savings rate is often lower than the disciplined engineer’s. A lower rate means a longer road.

•    The absolute number is daunting. “I need $10M to quit” feels impossible in a way “I need $2M” does not — even though the journey is identical. Many high earners never start because the target looks absurd.

•    More to lose by quitting. Walking away from a $500k salary to trade is a far larger opportunity cost than leaving $110k. The wage safety net you give up is worth much more.

•    The tax drag is heavier. Higher earners lose a bigger share to tax on both salary and trading gains, so each dollar works a little less hard.

The “Can I Quit?” Checklist

The arithmetic answers how much. This answers whether you are ready. Before handing in notice, you should be able to answer YES to every question below. A single confident NO means the decision is premature.

This checklist covers capital, income and personal readiness. The evidence your system must show first — out-of-sample results, realistic costs, live-versus-backtest behaviour — is the separate checklist in Part 3, and it comes before this one.

A note on the numbers

Every figure in this article is US-based — a US salary, US tax rates, US health-insurance costs, US retirement rules. The specific numbers will differ in Singapore, Europe or elsewhere; a reader should substitute their own. But the structure of the argument does not change: a system’s average return is not a salary, drawdowns arrive at the worst time, quitting removes benefits you were not counting, and the capital required to survive a bad sequence is far larger than the naive calculation suggests. Those hold in every currency.

Disclaimer: Education, not financial advice. All figures are illustrative and depend entirely on the assumptions in Section 0 — especially the 16% CAGR (an assumption, not a promise) and the benefit-replacement costs (which vary widely by family, age and state). Tax rates are approximate; a full-time US trader may be able to elect trader-tax-status (IRS Section 475 mark-to-market) via an entity to deduct expenses — consult a tax professional, as this is situation-specific and changes the numbers. Markets, salaries, insurance and tax law change. Verify any headline return out-of-sample and net of costs before relying on it. Consult a licensed financial professional before making decisions.