# Phone-only popup form for loan leads: +5.5% submissions, -23.6% CAC

- Outcome: Won
- Page type: Lead form (Lead-gen)
- Elements: Form fields, Popup, Supporting copy
- Date shared: 2026-05
- Test run by: [Mercantil Bank](https://liftarchive.com/practitioners/mercantil-bank/)
- Commentary by: LiftArchive (our analysis, not theirs)
- Original source: https://blog.croct.com/post/case-study-mercantil-form-ab-test
- Page: https://liftarchive.com/test/mercantil-bank-phone-only-popup-form/

Mercantil Bank replaced a multi-field lead form with a popup that asked only for a phone number, and form submissions rose 5.5% while customer acquisition cost fell 23.6%. The bank's CRO team, with analyst Flávio Moreira, ran the A/B test using Croct, and it was published on the Croct blog. The popup also added copy explaining the loan, so the result comes from both changes together.

## Result

**+5.5% submissions, -23.6% CAC**

- Form submission rate: +5.5%.
- Qualified lead rate: +15.8%, so fewer fields did not hurt lead quality.
- Cost per qualified lead: -17.5%.
- Customer acquisition cost: -23.6%.

## Control

Landing page buttons led to a form with several fields that had to be filled in before visitors could reach the bank on WhatsApp.

## Variant

A popup asked only for a phone number. It also explained the product and what the loan simulation would show.

## Why it likely won (our reading)

- One field takes far less effort than several, so more people finish the form.
- Explaining what the loan simulation shows answers doubts that research had found, which the bank says helped qualify leads.
- The remaining details can be gathered later on WhatsApp, once the person is already talking to the bank.
- For an audience aged 50 and over on mobile, a single short step is likely easier than a long form.

## Caveats

The field cut and the new explainer copy were tested together, so their separate effects are unknown. The vendor published it without sample size or significance; the test ran in phases from reduced traffic up to 100%.

## How to run this test

- Hypothesis: If we cut our lead form to just a phone number and add short copy on what the lead will get next, then more visitors will submit, and lead quality will hold, because effort drops and expectations are clear.
- Primary metric: Form submission rate
- Guardrail: Qualified lead rate
- Guardrail: Cost per qualified lead
- Guardrail: Contact rate on follow-up
- Who should test it: Lead-gen businesses in finance, insurance or services that follow up by phone or messaging. Skip it if you need several details up front to route or qualify leads and can't collect them later.

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Credit: Mercantil Bank ran this test and owns the result. Summary and commentary by LiftArchive (https://liftarchive.com/test/mercantil-bank-phone-only-popup-form/).
Usage: Free to use, quote and build on, with credit and a link: name the practitioner or organization that ran the test and link to its LiftArchive page. The results belong to the practitioners who ran and shared them; the summaries and commentary are LiftArchive's.