---
title: "Seed universe"
description: "A seed universe is the starting pool of instruments a screener filters within — the set it searches before any filter runs, and the ceiling on what it returns."
canonical_url: "https://fincanva.com/docs/strategies/seed-universe"
last_updated: "2026-08-02"
md_url: "https://fincanva.com/docs/strategies/seed-universe.md"
---

# Seed universe

A seed universe is the starting pool of instruments a [screener](/docs/getting-started/screener) filters within — the set it searches before a single filter has run. A screener never scans the whole market unless the seed universe *is* the whole market: it evaluates its filters only against the instruments in the pool it was handed, so the pool is the ceiling on everything the screener can ever return. The app labels this pool **Universe**; what a universe is and how filters narrow one is covered in [Universe](/docs/getting-started/universe).

**Also seen as:** Universe, screening universe, starting pool, candidate set

## Where does a screener start hunting?

In whichever pool you hand it, and there are two ways to hand it one.

- **[Universe filters](/docs/screeners/universe-facets).** You choose an asset class and, optionally, narrow it further — on things like where instruments are listed, the exchange, the asset subtype, index membership, sector, and trading currency. Add none of those and the pool is the whole asset class; the app confirms that state with "No further universe filters".
- **A hand-picked list of instruments.** The instruments you choose *become* the pool. The screener then filters inside that pool: only instruments you added there are ever considered.

Either way the screener's [filters](/docs/getting-started/filter) run inside the pool and can only shrink it. A filter never reaches outside to pull in an instrument the pool excluded — which is why two identical screeners on different seed universes return different [matches](/docs/screeners/matches).

## What happens to my universe filters in Easy mode?

The screening card runs in two modes, **Easy** and **Pro**, and moving from Pro to Easy changes how the pool is defined. The switch dialog lists what Easy hides — extra Include screeners, Exclude screeners, custom max-hold and reinvest-delay timings — with a general framing of "Easy mode hides these Pro settings. They're kept and restored if you switch back to Pro:". The universe line is worded differently from the rest: "Your screener's universe filters will be dropped — in Easy, your picked instruments are the universe."

So in Easy the pool is your picked instruments, and in Pro the pool can additionally be defined by universe filters. Whether the filters survive a round trip back to Pro is not something the app's copy settles — that open point is recorded as a pending fact on this page rather than guessed at here.

## Why does the seed universe change results?

Because it decides what was ever eligible. A screener's output is a subset of its seed universe, so widening the pool can only add candidates and narrowing it can only remove them — and a strategy then allocates across whatever came back, using its [allocation method](/docs/strategies/allocation-and-allocation-method). A screener that looks unproductive may simply have been pointed at a pool with few instruments that could satisfy its filters.

## Defaults in Fincanva

- With no universe filters set, the pool is the entire asset class you chose — "No further universe filters".
- A universe edit is a draft until you commit it: **Apply** commits the change, **Cancel** discards it.
- Editing the universe of a screen inside a strategy changes only that strategy's own copy of the screener. It never rewrites the saved screener the copy came from — see [Attaching a screener](/docs/strategies/attaching-a-screener-to-a-strategy).
- Some asset classes have no further universe filters to offer, in which case only the asset-class choice applies.

## Worked example

A screener has one filter: revenue growth above the market median. You point it at a seed universe of all US-listed stocks — several thousand [instruments](/docs/getting-started/instrument) — and it returns several hundred matches, which the strategy then allocates across.

You keep the identical filter and swap the seed universe for a hand-picked list of 30 instruments. Now at most 30 instruments can be tested, so at most 30 can match, and in practice perhaps twelve do. Same filter, same date, same market data — a different result, because the pool the screener started from was different. Nothing in the first run's several hundred matches can appear in the second unless it was one of your 30.