Sky News understands that Ravelin, which counts companies including Deliveroo and Booking.com among its clients, is working with Evercore on a potential transaction.
Tech industry sources said a sale was among the options being explored by Ravelin.
Set up in 2014, Ravelin uses machine learning to help its users detect fraud when processing online payments.
The company was named after a type of fortification used on medieval fortresses to protect those inside.
To date, it has raised close to £30m through three funding rounds, the latest of which was announced last year.
Ravelin's shareholders include Draper Esprit, Amadeus Capital Partners and Passion Capital.
The potential valuation of any future fundraising or sale was unclear on Monday.
Ravelin chief executive Martin Sweeney said: "We work with Evercore as an advisor for Ravelin to help us evaluate any opportunities that might arise as we continue to grow and attract market attention.
"This is standard practice for fast-growing technology firms and not indicative of any imminent activity."