FOMO and the Arithmetic of a Chase

The signature of a chase

A chased entry is recognisable before it is expensive, and the signature is always the same three parts. There is no written setup, because the decision arrived while the move was happening. The price is already extended, so the entry is not at a level but in the middle of a run. And the stop is decided after the entry, or never, which means the size is decided after the entry too — and a size decided under time pressure is decided by the move rather than by the budget. The mechanical cost is worth computing because it is larger than the emotional one. Risk per trade is a fixed number of dollars, and the stop distance is the divisor. A late entry with a tight stop therefore buys a larger position: in the worked case $500 of risk buys 320 shares at $52 with a 3% stop, against 167 shares at $44 with a $3 stop, a notional exposure more than twice as large. Nothing about the risk budget changed and nothing about the view changed; the market exposure is simply 2.27 times bigger, which is the opposite of what a trader who feels late is trying to achieve. There is a second cost that is subtler and more damaging. The run that produced the chase was a period of above-average volatility, and a 3% stop is inside the ordinary movement of a stock in that state. So the position is likely to be stopped by noise rather than by being wrong — and, having been stopped, the trader is now watching the same move with a fresh loss to recover, which is where the next lesson begins. The honest accounting of a chase is therefore not the entry price paid; it is a larger position, an exit more likely to be triggered by noise than by evidence, and a loss that arrives while the move is still visible. One budget, two plans — Move from the base to the chase entry: ($52 − $40) ÷ $40 = 30% ← · Risk a share on the chase: $52 × 3% = $1.56 · Shares for $500 of risk: 320.5 shares — a $16,667 notional ← · Shares at the base break, stop $41 from $44: 166.7 shares — a $7,333 notional · How much larger the chase notional is: 2.27× The comparison is the point rather than the numbers: two entries, one risk budget, and a difference in exposure that the trader never chose. Sizing off a tight stop is the way a decision to feel less exposed produces more exposure.

What to do instead

The first answer is the one that sounds least satisfying: if the move has removed the entry, the trade is gone rather than the risk having gone up. A setup is defined by the price it occurs at, so an entry that requires a price 30% higher is a different trade with different odds, and the right comparison is between that new trade and every other use of the capital. The missed move is a zero-loss outcome, which is a much better result than the position that a chase typically produces. The second answer is mechanical, and it works when the trader does decide to act: size off the stop you would have used at the setup, not the stop that is comfortable from here. If the base-break plan had a $3 stop, then the width of that stop, not a 3% figure chosen to make the risk feel small, is what divides the budget — and if the arithmetic then says the position is a third of what the chase implied, the arithmetic is describing the actual risk rather than reducing it. The rule underneath is that the stop comes from the chart and the size comes from the stop, so neither can be adjusted to make the other feel better. The third answer is the one that prevents the situation. A written plan for the setup, prepared before the move, means the entry price was not a decision made in the middle of one; and a watchlist with defined triggers means the attention that a run attracts is spent on the plans already written rather than on a new one assembled at speed. FOMO is not solved by being slower to feel excitement. It is solved by having the decision already made, because a plan that exists does not have to be invented while the price is running. • If the move has removed the entry, the trade is gone — a missed move is a zero-loss outcome. • If you do act, size off the stop the setup would have used, not the tightest stop available now. • The chart picks the stop and the stop picks the size; neither is adjusted to suit the other. • Write the plan before the move, and keep a watchlist with defined triggers. A tight stop on a late entry is the most seductive form of leverage in retail trading, because it makes an outsized position look conservative. Check the notional exposure rather than the risk figure: the risk is the same either way, and the exposure is what the account carries.

The scoreboard you were shown

FOMO is fed by a biased sample, and the bias is structural rather than personal. The people who post their outcomes post the ones worth posting, so the winners are visible and the losers are private; the position that went up is discussed and the position that went nowhere is forgotten. You are not comparing your whole record with somebody’s whole record. You are comparing your complete knowledge of your own performance, including every boring week and every mistake, with a curated highlight reel from other people. That comparison is not winnable, and it has nothing to do with whether the trade being chased is a good one. A second asymmetry is in memory. A missed winner is remembered long after a missed loser is forgotten, because the missed winner has a visible price attached to it that keeps issuing a correction — the chart keeps updating and it keeps saying you were wrong. A trade you correctly declined that went nowhere leaves no evidence at all. Over a few years this produces a systematic overestimate of how much good trades were avoided rather than taken, which is exactly the belief that makes chasing feel rational. The structural fix is to make the decision before the move, which is what a watchlist with written triggers does. If the condition for buying a name is written down at a price and a setup you chose in advance, then the moment the price runs is not a decision at all — it either met the condition or it did not, and a chase is simply a trade that failed its own test. The emotional content of the moment stays, since nothing removes that, but it no longer has a vote. What FOMO cannot survive is a pre-written condition, because a pre-written condition does not care how fast the price moved. • You see other people’s winners and your own whole record; that comparison is unwinnable. • Missed winners leave a visible price to be regretted; missed losers leave no evidence. • Over time that memory asymmetry makes chasing feel justified. • A pre-written trigger removes the moment from the decision entirely.

The machine that produces the feeling

The feeling is treated as a personal failing, and it is better understood as the output of an industry. A great deal of money is spent making a small number of price moves extremely visible, and the visibility is not a neutral fact about the market — it is manufactured, because attention is what sells advertising, subscriptions and newsletters. The first mechanism is the **selection of what gets shown**. The lists, the tickers and the trending symbols are built from what has already moved, which means the visible set is precisely the set that has already paid. A stock that tripled is on the front page; the ten thousand that went sideways are not, and neither are the ones that tripled and then gave it back. The sample you are shown has been selected on the outcome, so its average outcome is not the market’s — it is the best part of the market’s distribution, presented as though it were typical. The second is the direction of the incentive. The people producing the content are paid for attention, and a call that produces a large return in a month generates far more of it than a position that works over three years. The consequence is structural rather than conspiratorial: the loudest voices in the system are the ones whose time horizon is shortest, because that is the horizon that produces clicks. Nothing about this requires anyone to be dishonest. The third is survivorship in the audience’s own observation. You see the people who posted their winners and not the ones who did not post, so the community you are comparing yourself against is itself a selected sample. The same logic applies to your own memory of your decisions, which retains the positions you considered and discards the ones you never opened. The useful response is not to stop reading, which is unrealistic, but to change what you measure yourself against. A benchmark set in advance — an index, or your own written process — replaces a social comparison with a standard. And the specific test for a chase is worth keeping in the same place: was the position part of the plan before the move became visible? If the idea arrived with the price, then what arrived was the advertisement, not the analysis. • The visible set is selected on having already worked, so it is not a sample of the market. • Content is paid for attention, and attention favours the shortest time horizon. • You see the winners people posted, and remember the positions you thought about. • Replace social comparison with a benchmark set in advance before the move appeared. The inverse relationship is worth holding onto: the more visible a move has become, the more of its return has already been delivered to somebody else. Visibility is manufactured from realised returns, which are the one thing that cannot be bought after the fact.

Sources

• Chasing and the disposition of attentionOdean (1998) and subsequent trading-behaviour research
• Position sizing from stop distanceVan Tharp, “Trade Your Way to Financial Freedom”
• Volatility, stop distance and noise exitsStandard risk-management practice; ATR-based sizing literature