Margin that depends on position size

[Fairman]

Margin that depends on position size

Leverage is often shown as a single number: 1:500, 1:100. On some brokers, it's tiered. Small positions get the full leverage, and larger ones get less.

An account might have 1:500 up to a notional of 100,000 dollars, 1:200 up to 500,000, and 1:100 beyond. Adding a second position can change the margin on the first, in a way the position size alone doesn't suggest.

Scalpers who scale up around high-conviction moments can run into this. The extra lot costs far more margin than the previous one, and the free margin figure shrinks faster than expected.

Tiered margin also interacts with stop-out. A position that was fine at one size becomes borderline at the next tier, because the margin requirement of the whole position resets at the new, higher rate.

The tier table is in the account terms or on the symbol specification. It's easy to miss because most traders never approach the thresholds.

For anyone planning larger sizes, a quick calculation with the actual tiers avoids the unpleasant discovery in the middle of a trade.

Which tier boundaries apply on the account used here, and have they ever come into play?

[Amanhasnoname]

This caught me out once, and it was not a pleasant few minutes. I was adding to a GBPUSD position during a strong London move and the third lot used far more margin than the first two combined. I hadn't realised that crossing the tier repriced the whole position, not just the extra lot, so my free margin dropped much further than my rough mental maths said it would.

Nothing was stopped out, but my margin level went from comfortable to under two hundred percent in one click, and I closed the add straight away because I couldn't think clearly about it. After that I went and found the tier table, which on my broker was buried in the symbol specification rather than the account page.

What I do now is keep a small spreadsheet with the tier limits and my usual position sizes, and I check it before any day I expect to scale up. My account starts reducing leverage above a fairly low notional, so it matters more than I would have guessed for a retail size account.

[Shadow Trader]

In many jurisdictions, regulators capped retail leverage on major pairs at 30:1, with lower limits for minor pairs and exotics. Offshore entities still offer 500:1 or more. The gap changes how a scalping account behaves.

At 30:1, a 1 percent adverse move can wipe the margin on a fully used position. Scalpers using tight stops can still operate comfortably, but the capacity to hold multiple positions simultaneously shrinks, and margin calls come quickly when several trades are open.

Higher leverage doesn't create an edge. It creates room for mistakes that are bigger and faster. Still, a few strategies, such as running several simultaneous positions across correlated pairs, rely on margin headroom that a low-leverage account can't provide.

Another effect: margin requirements can change around news or weekends. A broker may reduce leverage ahead of major events, and an account that was fine at 30:1 suddenly needs more margin at 20:1, triggering stop-outs on positions that hadn't moved.

Checking the current margin requirement per symbol, and whether it changes at specific times, gives a more accurate picture than the headline leverage.

Margin also behaves differently depending on the type of position. Some brokers allow margin offsets for hedged positions, where a long and a short on the same pair require margin only on the larger side. Others charge full margin on both. For strategies that use hedging as part of the routine, the difference determines how many positions fit within the account.

The currency of the account matters, since margin is computed in that currency and changes as exchange rates move. A position that required a certain margin in the morning might need slightly more in the afternoon.

For scalpers, free margin is the key number to watch, not the nominal leverage. It determines how many positions can be opened in a burst, such as during a fast market when several entries are triggered in a row.

A table showing the margin per lot on each symbol, updated whenever the broker changes it, belongs next to the position size calculator.

How much leverage does the strategy actually need, and how much does the account provide?