Trailing Drawdown

TL;DR. Trailing drawdown is the prop firm rule that follows your peak equity upward but never moves down. The Robustness Prop Firm panel models three real-world variants — intraday, end-of-day, and locks-at-start — because they kill different strategies for different reasons.

What you'll be able to do

• Distinguish the three trailing variants and name which firms use each.
• Predict which trailing variant will be the failure mode for your strategy type.
• Read the failure breakdown on the Prop Firm panel and tie failures back to specific intraday behavior.

What trailing drawdown means

Most prop firms have a hard maximum drawdown rule: lose more than $X from peak equity and your account is closed. The "trailing" part means the peak isn't fixed at your starting balance — it moves up as your equity grows.

You start with $50,000 and a $2,000 trailing drawdown. The floor is $48,000. You make $1,000 in profit, equity = $51,000, peak = $51,000, floor = $49,000. You make another $500, equity = $51,500, peak = $51,500, floor = $49,500. Now you lose $1,200, equity = $50,300 — still above floor $49,500, you're fine.

Now imagine you lose another $1,000, equity = $49,300 — below the floor. Account closed.

The trailing structure is asymmetric: profits raise the floor permanently; losses don't lower it. That makes the rule progressively harder to survive as you trade. The deeper into profit you go, the smaller your margin against a normal drawdown.

The three variants

Different firms implement trailing differently. The variants matter because they kill different strategies.

Intraday-tracking (Apex)

The peak tracks unrealized equity in real time. The moment your unrealized PnL prints a new high — even if you give it back before close — the trailing floor moves up.

This is the most punishing variant. A strategy that prints +$800 unrealized intraday, draws down to +$200, and exits at +$200 still has its trailing floor raised by $800 worth of margin. Mean-reverters with frequent intraday excursions get killed by this even when their realized PnL is positive.

End-of-day snapshot (Topstep)

The peak tracks realized end-of-day equity. Intraday excursions don't count — only the closing balance. A strategy can print +$800 unrealized, draw down to +$200, exit at +$200, and the trailing floor moves up by only $200.

This is easier on strategies with high intraday variance. The cost: Topstep also enforces a daily loss limit ($1,000 on the 50K combine), so the easier trailing is balanced by a tighter loss cap.

Locks-at-start (MFFU's variant)

The trailing peak starts moving with profits, but freezes the moment your equity reaches a defined "lock" threshold (usually starting balance + the trailing distance). After the lock, the floor is fixed at your starting balance forever — no more trailing.

This variant is most forgiving for strategies that quickly build up an initial cushion. Once you cross the lock threshold, you can take any drawdown back to the starting balance without failing. The downside: reaching the lock requires accumulating the full trailing distance in profit before any meaningful drawdown.

Which variant kills which strategy

The matching between strategy type and trailing variant is one of the most actionable insights on the Prop Firm panel. Some patterns:

• Mean-reverters with frequent intraday excursions → killed by intraday. Apex is usually the worst choice for this strategy type even when its other rules are favorable.
• Slow swing strategies that hold across days → fine under intraday because they print fewer high-frequency unrealized peaks, but exposed to end-of-day if any single bad day moves the floor up substantially.
• Burst strategies that accumulate profit fast → favor locks-at-start because they can reach the lock threshold quickly and then have unlimited drawdown headroom.
• Steady-grinder strategies → fine across all three variants because they don't produce sharp intraday excursions or fast accumulations.

The Failure Mode Breakdown on the Prop Firm sub-tab makes this explicit. For each firm, the panel shows the percentage of failed sims attributed to each rule. If "Trailing DD" is the dominant failure cause at Apex but not at Topstep, you have the diagnosis: it's the intraday variant specifically that's killing this strategy.

In AlgoLift

Trailing drawdown logic lives in the per-firm replay kernel — a Numba-JIT state machine modeling each firm's exact rule priorities. The Robustness Lambda applies all four firms' rules in parallel to your resampled trade lists, producing per-firm pass and survival rates.

• The Prop Firm sub-tab's comparison rings show pass rate per firm, with the best-fit firm highlighted.
• The failure breakdown small multiples show which rule killed your failures at each firm.
• The headline verdict card picks the best-fit firm and explains why in plain English, often citing trailing variant as the determining factor.

Reading the failure breakdown

The failure breakdown sums to 100% of failed sims per firm. The dominant rule for a given firm tells you the binding constraint for that combination:

• Trailing DD dominant at firms with intraday trailing (Apex, MFFU) → your strategy prints intraday excursions that the trailing floor catches.
• Trailing DD dominant at firms with EOD trailing (Topstep) → your strategy has bad-day drawdowns that move the floor up before recovery.
• Daily Loss dominant → your strategy has occasional large-loss days; the firm's daily loss limit triggers before trailing does.
• Consistency dominant → your strategy's profits concentrate in single days that exceed the firm's consistency cap (Topstep specifically).
• Timeout dominant → your strategy runs out of trading days before hitting the profit target. Common for slow strategies under FTMO's 30-day window.

Worked example

What this shows. The same strategy has very different relationships with each firm's rule set. Apex has the best raw pass rate but failure is dominated by intraday trailing — a fundamental mismatch with the strategy's profile. Topstep's pass rate is slightly lower but failure mode shifts to daily loss, which is a rule the strategy could defend against more easily with a daily loss limit override. FTMO is the worst — both a low pass rate and a fragmented failure profile suggest the strategy is structurally incompatible with FTMO's rules. MFFU is competitive with Apex on raw pass rate and has a less-dominant trailing failure, making it the second-best fit overall.

Common misunderstandings

• "All trailing drawdowns are basically the same." No. The intraday variant can fail a strategy whose realized PnL is positive — the same strategy with EOD trailing wouldn't have failed. The variant matters.
• "I should pick the firm with the largest trailing distance." Sometimes. But a larger trailing distance often comes with tighter daily loss or consistency rules. The Prop Firm panel computes the joint probability of pass × survive specifically to bypass this kind of single-rule fixation.

When trailing drawdown is the binding constraint

• Strategies with frequent intraday excursions. Apex's intraday variant will be the dominant failure mode.
• Strategies with rare but large losing days. EOD variants at Topstep let intraday volatility through but punish bad-day drawdowns.
• Strategies that take time to accumulate profit. Both variants can trigger before the lock threshold is reached at firms that use locks-at-start.

When it matters less

• Strategies that reach the lock threshold quickly under MFFU-style rules. Once locked, trailing stops being the binding rule.
• Strategies with high consistency and low intraday variance. The trailing floor rises smoothly and never catches the strategy's natural drawdowns.