Phone-only popup form for loan leads: +5.5% submissions, -23.6% CAC
Commentary byLiftArchiveOur analysis, not theirsMercantil 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.
- 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%.
The change
Multi-field form replaced by phone-only popup with explainer copy
Simplified mockup drawn by LiftArchive from the shared screenshots.
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 of the result, not the practitioner's claim.
- 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%.
Who ran it
Mercantil Bank ran this test for Brazilian bank (loans for the 50+ audience) and published the results (Croct blog case study). The numbers are theirs; the summary and commentary on this page are ours.
Read the original case study on Mercantil Bank →
How to run this test on your site
- 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
- Guardrails
- Qualified lead rate
- Cost per qualified lead
- 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.
Questions
Does a shorter lead form lower lead quality?
Not always. Mercantil Bank cut its form to one field and its qualified lead rate still rose 15.8%, helped by copy explaining what came next.
What is a phased A/B test rollout?
You start the test on a small share of traffic, check for harm, then increase exposure step by step.
It limits risk when testing a critical form.
Should loan lead forms ask only for a phone number?
It can work if you follow up quickly by phone or messaging and collect the rest there. Test it against your own qualification needs.