Screener attach
A screener attach is a screener embedded in a strategy so that a rule, not a hand-picked list, decides what it may hold, re-evaluated at every rebalance. It sits in a qualifying pool, which brings instruments in, or a rejecting pool, which takes them out. Attaching copies the screener, so later edits to the saved one do not reach it.
Also seen as: In and Out screeners, Qualify and Reject
How do the qualifying and rejecting pools combine?
The candidate set is the union of what the qualifying screeners match, minus the union of what the rejecting screeners match:
- the instruments the strategy may hold at this rebalance
- the instruments in the working scope that match the i-th qualifying screener
- how many screeners sit in the qualifying pool
- the instruments in the working scope that match the j-th rejecting screener
- how many screeners sit in the rejecting pool
In words: an instrument is a candidate when it matches at least one qualifying screener and no rejecting one. The working scope is the basket if it holds instruments, and each qualifying screener's own universe otherwise. With no qualifying screener the candidates are the basket itself; with no basket either, the strategy has nothing to choose from and does not run.
How does Fincanva handle it?
- Attaching a screener to a strategy is not included on the Free plan. Free attaches none — a screener still runs on its own there — while Starter attaches 1, Advanced 2, and Ultimate and Professional 8. See what each plan includes and How does the Free plan show screeners in a strategy?
- Two cases run differently in the engine than the formula suggests — see When does the engine depart from the formula?
- A second screener in a pool widens the pool, because a pool matches on any of its screeners; a filter added inside one screener narrows it.
- A strategy on the screener path needs at least one attached screener before it can be saved and run: "Add at least 1 screener." How to attach one: Attach a screener to a strategy.
Which titles does an entry screener put into the positions?
The positions are filled from the qualifying screeners' result in its order, decided in two steps.
- The cap. When more titles pass than six times Max positions, the engine keeps only the most traded — highest average traded volume — in that order. The cap applies to all qualifying screeners together, not to each one.
- Your ordering row. A Highest / Lowest row — "is among the highest 10", say — keeps the first N titles of its own order: it is how you decide which titles are preferred. Without one, the order is the cap's by traded volume or — under the cap — an internal order of the index, which is not a merit.
So an ordering row decides only when its last row keeps no more than six times Max positions. Two alerts to review on the Asset selection card say where you stand: "No rule decides which names enter", when a qualifying screener has no ordering row, and "The engine does not keep the top of your ranking", when the last ordering row keeps more than the cap. With a Ranking-based Risk-On method the positions follow that method's own ranking, and both alerts stay silent.
With two or more qualifying screeners a title enters by passing any one, and the grey note "Passing any one of the screeners is enough to enter" says so: "A title enters if it passes at least one of the screeners, not all of them; to ask for both conditions, put them in the same screener."
What does it look like in practice?
A strategy's basket holds ten tickers, so that basket is the working scope:
AAPL · MSFT · NVDA · TSLA · JNJ · PFE · KO · WMT · XOM · GE
Two screeners sit in the qualifying pool and one in the rejecting pool. Suppose at this rebalance they match:
| Pool | Screener | Matches |
|---|---|---|
| Qualify | JNJ · PFE · KO · WMT · XOM | |
| Qualify | AAPL · MSFT · NVDA · TSLA | |
| Reject | TSLA · XOM |
The qualifying union is nine tickers — everything except GE, which matched neither, so it is never a candidate. Subtracting removes TSLA (a candidate via ) and XOM (a candidate via ), leaving seven:
AAPL · MSFT · NVDA · JNJ · PFE · KO · WMT
Those seven are what the strategy may hold at this rebalance. A Max positions cap applies on top: with the cap at 5, the strategy holds five of the seven. At the next rebalance the same three screeners are re-evaluated and the seven can be a different seven.
When does the engine depart from the formula?
In two cases, and each raises a strategy alert to review. The same screener in both pools: a title that passes both is sold and bought back in the same rebalance, so the entry wins, unless a reinvest delay of at least 1 month holds it out. A rejecting pool over a basket with no qualifying screener: the engine sells what matches it and buys the same instrument back in the same rebalance, because the candidates are always the basket and no wait applies there — so the pool changes nothing, and the alert reads "The exit screener changes nothing".
How does the Free plan show screeners in a strategy?
Visible and marked, never hidden. On the Asset selection card, Screen and Compose keep their place, each with the plan's bars after its name — hovering them reads "Available from Starter" — and choosing one opens it as a switched-off preview: the surface with the starter screener filled in, where nothing can be changed or saved. Pressing the bars, or the key you are already previewing, opens the plan dialog — "Strategies with screeners are available from Starter" — and choosing Basket brings back what the strategy holds. The Basket's Filters are hidden on Free unless the strategy already holds a screener.
A strategy that holds one anyway — made on a paid plan, or copied — is kept intact, but its backtest is refused before you press it; see plan compliance.
Used in 11 pages
- Bring a set-aside strategy back into your plan · Account and plan
- Screeners · Screeners
- Choose the instruments a strategy holds · Strategies
- Attach a screener to a strategy · Strategies
- Fix the Asset selection alerts · Strategies
- Asset-selection modes
- Exit reason
- Reinvest delay
- Screener
- Strategy alerts
- Strategy type
UPDATED 2026-10-07