The first thing you should do if you don't recognise a card transaction is lock your card from the Card screen in-app.
Now you can look further into the transaction. It's worth noting that merchants often appear under different trading names, so you may not recognise a transaction straight away when it appears on your statement.
To help with this, we have compiled a list of popular merchants and the names they trade under - https://help.starlingbank.com/hc/en-us/articles/360014683999
Have a look through this list and see if you recognise the company. If you are unable to find the merchant in this list it may also be worth searching the company online to see if you recognise the business.
Other things to check:
Subscriptions/Free trials, have you signed up to any free trials recently? Check these haven’t rolled over into a paid service.
Recurring payments, did a similar payment amount leave the account last month? Check if there are any ongoing payments that may have been arranged on a recurring basis.
Offline transactions, if you made a transaction with a merchant who uses an offline terminal (such as Transport for London or airlines), it can take a few days for these transactions to appear on your statement.
After following the above steps if you still don't recognise the transaction amount or the merchant, get in touch with our customer service team so we can investigate.