Every investor wants a shortcut.

A magic filter that spits out the next 100-bagger while you sleep.

I’ve spent years using screeners. They’ve led me to some of my best ideas. But they’ve also taught me something important:

Screeners are a starting point, not a destination.

Today I’m sharing my personal multibagger screener - completely free - along with some honest thoughts on what screens can and can’t do for you.

At the end of the post, I've also pulled out 10 of my favourite ideas from the list with mini-theses on each.

The Case For Screening

Screens can work. Here’s why I still use them:

• They filter noise. There are thousands of publicly traded companies. Screens narrow the universe to something manageable.

• They enforce discipline. When you define your criteria upfront, you avoid chasing stories that don’t fit your framework.

• They surface the overlooked. Small and micro-caps get zero analyst coverage. A well-designed screen can surface names you’d never stumble across otherwise.

• They’re repeatable. Run the same screen monthly, and you’ll catch businesses as they enter your criteria.

For idea generation, especially in the small-cap space, screens remain one of the best tools available.

Why Small-Caps Are Different

Here’s the thing: for large caps, screening is almost pointless. Every metric is picked over by hundreds of analysts with Bloomberg terminals and better data than you.

But small and micro-caps? That’s different.

These businesses are structurally ignored by institutions. Fund mandates prevent them from buying. Liquidity constraints keep them off the radar. Analyst coverage is sparse or non-existent.

That means inefficiencies persist.

A screen that surfaces a £50M company with 25% ROIC and 30% growth isn’t competing against Goldman Sachs. It’s competing against... almost no one.

For idea generation in small and micro caps, screening still works in my opinion.

Not as a magic formula. But as a starting point for real research.

The Limits of Screening

But here’s the uncomfortable truth: the best multibaggers often don’t screen well.

Why?

• Qualitative moats don’t show up in data. A founder’s capital allocation brilliance, a unique culture, a regulatory tailwind - none of these appear in a screener.

• Transformation stories get filtered out. A business tripling margins won’t show high historical ROIC. A turnaround won’t pass profitability filters.

• Narrative complexity breaks formulas. The most asymmetric opportunities usually require context that spreadsheets can’t capture.

• Management quality is invisible. Insider ownership shows up, but alignment, integrity, and long-term thinking don’t.

My Multibagger Screener

Here’s a mistake I see constantly: investors build screens with “perfect” metrics baked in.

The result? A screen that returns 3 stocks - all of which everyone already knows about.

My approach is different: cast a wide net, then do the work.

I use a deliberately rough screen. Simple filters that get me into the right universe - small caps with growth, decent margins, and financial stability - without filtering out the interesting edge cases.

Here’s exactly what I use:

• Market Cap $10M – $1B: This is where inefficiency lives. Too small for institutions, too obscure for analysts. The structural neglect creates opportunity.

• 15%+ Revenue CAGR (3Y): I want businesses with momentum. Not explosive growth that screams “priced in”- just steady compounding that suggests something’s working.

• 30–100% Gross Margins: A rough proxy for pricing power and business quality. Sub-30% margins usually mean commodity economics. Above 30% suggests something defensible.

• Net Debt / EBITDA 0–2x: Conservative leverage. I’m not looking for debt-free businesses exclusively - some leverage is fine - but I want to avoid balance sheet risk.

• Positive Free Cash Flow: Cash generation matters. This filter alone removes the cash-burning growth stories that rarely end well.

• Geographic Scope: I focus on markets I can research effectively - North America, Europe, and Latin America. This also captures overlooked exchanges like the TSX-V, AIM, and Euronext Access where many of my best ideas have come from.

As of today, there are 111 stocks in this list.

That’s 111 potential ideas. 111 starting points. Not 111 guaranteed winners - but 111 businesses that might worth investigating further.

The screen is free. Use it however you like.

You can view the full screener here: Koyfin Multibagger Screen

What This Screen Doesn’t Filter On (And Why)

You’ll notice my screen doesn’t filter on ROIC or P/E.

But I do include them as columns in my view. I want to see these metrics - I just don’t want to filter on them.

Here’s why:

ROIC and P/E are easily distorted by short-term noise.

A business mid-turnaround might show 8% ROIC today - but that same business could be running at 20%+ within 18 months as margins normalise. Filter on “ROIC > 15%” and you’d never see it.

A company reinvesting heavily in growth might show a 40x P/E - but strip out the one-off costs and the underlying earnings power looks completely different. Filter on “P/E < 20” and you’d screen it out.

These metrics matter. But they’re lagging indicators that reflect where a business has been, not where it’s going.

I’d rather see the “ugly” numbers and investigate than filter them out and miss the opportunity.

A Quick Thank You

We’re about to hit 18,000 subscribers.

The page is off to an incredible start to the year, and I can’t thank you enough for the support.

We’ve also seen a surge in paid subscribers - nearly 50 new members in the last couple of weeks alone.

Join and Upgrade Now!

This kind of growth encourages me to keep producing free, valuable content like this screener.

Also, if you found this post useful, I’d genuinely really appreciate a like or restack. It helps the page more than you know and makes content like this possible.

My 10 Favourites From the List

111 stocks is a lot to sift through.

So I’ve pulled out 10 names that caught my eye - businesses I either have direct experience researching or I find interesting.

Some of these I’ve written about before. Others are fresh ideas worth watching.

Here’s the breakdown:

1. Innovative Aerosystems (ISSC)

A small aerospace manufacturer designing flight management systems, cockpit displays, and autothrottles for both retrofit and OEM applications. What interests me here is the setup: new management has built out the infrastructure (Exon facility complete, ERP system in place) and demonstrated an ability to execute value-add M&A on orphaned aerospace assets - exactly the kind of overlooked, complex deals larger players ignore. They've guided to $250M revenue and ~$70M EBITDA by 2029, which implies significant growth from here. The near-term is noisy - military contract timing creates quarter-to-quarter lumpiness - but the medium-term drivers look compelling: expanding sales team building an organic pipeline, new cockpit automation platforms in development, and continued M&A optionality. In my view, this is a bet on management's ability to consolidate a fragmented corner of aerospace at attractive multiples. Company is quite high up my research pipeline.