First let's understand what is doing the jumping. So we'll start with the definitions, then get to the interesting part - the characteristic shape of a jump, and why that shape might hand a patient private investor an edge.
A quick refresher on StockRanks
Every share in our universe gets a StockRank - a score from 0 to 100 that ranks it against every other stock in the market. The headline rank is the QVM, which blends three factors that decades of academic work and our own data tell us matter: Quality (is this a good business?), Value (is it cheaply priced?) and Momentum (is the market warming to it?).
A QVM of 95 means a stock sits in the top 5% of the market on that combined picture of quality, value and momentum. A QVM of 33 means it's in the bottom third. The rank updates as the underlying data updates - new results, new prices, new estimates - so it moves over time as the story changes. It is not a recommendation and not a target price. It is a snapshot of where a company's fundamentals and technicals stand against every one of its peers, refreshed every day.
Two thresholds matter for this study:
80 and above is the top quintile - the top 20% of the market.
90 and above is the top decile - the top 10%.
Think of the top decile as the VIP room - the 90+ club. It's where the historically best performing stocks sit. The question this whole series asks is simple: when a stock jumps into that room, quickly, does the size and speed of arrival tell you anything the room itself doesn't?
A leap versus a creep
Here is the distinction that the entire study turns on.
A stock's rank can rise two ways. It can creep - drift up a point or two a week as the data slowly improves, easing over the 80 or 90 line almost imperceptibly. Or it can leap - jump a meaningful number of points in a single step, the way a rank moves when a profit upgrade, a strong set of results or a genuine change in the business lands all at once.
We defined a jump precisely: a move of at least 5 rank points within a single weekly grid step, a 5-to-10-day window, that carries the stock up across a threshold. We then sorted those jumps by size:
+5 to +10 points - a nudge over the line.
+10 to +20 points - a real step up.
+20 to +40 points - a big re-rating.
+40 and above - a violent move (and, it turns out, often a warning).
The reason this distinction matters so much is that the two behaviours are telling you completely different things. A creep is the market having a slow, gradual change of heart - by the time the stock crosses the line, the news is months old and largely in the price. A jump is the market reacting to something concrete that just happened. And because fundamental news tends to reprice slowly in smaller companies, that fresh information often has further to run. Hold that thought, because it is the whole game.
The shape of a jump
If you watched a classic jumper on a chart, with its rank plotted underneath the price, you would see a shape that repeats again and again across the study.
For months, nothing. The company sits quietly mid-table, a rank somewhere in the 60s, unloved and largely unwatched. Then, in the space of a single week, the rank leaps into the top decile - a set of results, or a broker estimate revision that changes the numbers. That is the moment we count as the jump. And here is the part that matters: the rank stays there. This is less often a share price that spikes and falls back. It arrives in the decile because the thing that lifted the rank was most likely a real change in the business, rather a flicker in the price.
Now about the price. On the day of good news it often moves - of course it does. But it does not finish its move that day. It keeps drifting higher, week after week, for months. Across the whole population of jumpers, a stock that leapt into the decile was on average about 18% higher a year later. Not on the day. Over the following twelve months, in a patient grind.
That is the anatomy in one line: the jump is the market noticing. The drift is the market slowly agreeing. The sharp leap is the crowd registering that something changed. The long drift afterwards is the crowd, grudgingly and in stages, coming round to how much it changed. And that gap - between the noticing and the agreeing - is where a rules-based investor can profit.
Why the drift happens
A drift you can't explain is a drift you shouldn't trust. If a share simply floated 18% higher over a year for no reason, we'd expect it to be arbitraged away the moment enough people spotted it. So the honest question is: why is the price so slow? Why doesn't it just jump the full distance on the day and be done?
Three well-documented forces conspire to stretch a one-day surprise into a months-long trend. None of them is our invention. They're human, they're old, and they're stubborn.
First, post-earnings-announcement drift. This is one of the most replicated findings in all of market research: after a genuine earnings surprise, prices move in the right direction, but they don't move far enough or fast enough. A company beats, the shares pop 8% on the day, and then they keep on climbing for weeks as the market finishes doing the analysis it should have done at the open. The initial reaction is real but incomplete. The rest of the information is accepted slowly, and that causes the drift.
Second, analyst anchoring and adjustment. Analysts build careful, detailed forecast models, and they are reluctant to tear them up. So when reality comes in ahead of the model, they revise their numbers up - but only partway. Human beings anchor to a starting estimate and adjust too little from it, and analysts are human beings with much loved spreadsheets. The consequence is a slow-motion catch-up. A company that has genuinely stepped up its earnings power comes in "significantly ahead of expectations", the analyst nudges the forecast up a bit, and then next period the company beats again, because the forecast still hasn't caught reality. Beat, nudge, beat, nudge - each upgrade dragging the price up another notch - until the models finally sit level with the business. In an under-researched small cap, where one or two part-time analysts (if at all) might cover the name, that catch-up can take a year. The rank knows before the calendar does, because the rank reads the results the day they land, while the consensus is still edging up towards them.
Third, the disposition effect. This is the quiet one, and it might be the most powerful. Investors love to sell their winners and hold their losers - it feels good to bank a profit and painful to crystallise a loss. So when a stock jumps, its existing holders start selling into the strength to lock in a quick gain, capping the rise. Meanwhile the buyers who might replace them are anchored to the old, lower price and feel they've "missed it", so they hesitate and buy in dribs and drabs. Put those two together and you get a very particular imbalance: too much selling from the people who already own it, too little buying from the people who don't. Expectations reset one careful step at a time, and that is exactly the recipe for a smooth, grinding trend rather than a single clean jump to fair value.
You can watch all three at once in a name like Yü Group, the small-cap energy supplier we'll return to later in the series. It jumped into the top of the decile in October 2022 on a step-change in profitability, then delivered "significantly ahead of expectations" update after update while analysts inched their forecasts up behind it and early holders banked their gains too soon. The rank held the decile for a year while the price ran up nearly sixfold. The jump was the data noticing. The 12-month drift was the market, slowly, agreeing.
Buy the leap, not the creep
Now put the shape and the mechanism together, and the intuition behind the whole series falls into place. A jump is the market reacting to something concrete and fresh, in a corner of the market too neglected to price it instantly - so the reaction has room to run. A creep is the opposite: a slow drift where whatever changed is already weeks old and already in the price. There is no fresh surprise left to leak out, no analyst catch-up still to come, no under-reaction to exploit. The freshness that powers the drift simply isn't there.
That is the seed of the rule we'll keep coming back to: buy the leap, not the creep. A sharp jump into the top decile may be flagging a re-rating that has only just begun. A gentle drift over the line is, more often than not, the tail end of a move that's already played out.
But intuition is cheap. Plenty of plausible market stories evaporate the moment you test them against the data - and this one comes with an obvious objection: surely the big losers are hiding in here too, the profit warnings that turn into collapses, the falling knives. They are. So before we turn any of this into rules, we have to prove the jump effect actually exists, at each jump size, measured against a fair control group, with every failure and every delisting left honestly in the sample.
That's the next chapter.
Next: Chapter 2 - The evidence. How we measured every jump, why we kept the delisted stocks in the sample, and how we stopped ourselves from fooling ourselves.