Data I obtained from thirteen of the biggest banks on the Polish market suggests that in September they had a total of 9.2 million customers who logged in to their accounts from a mobile device at least once during that month. It's an increase by approximately 0.25 million compared to June, when there were almost 9 million mobile customers.

Related: Polish Banks Have Almost 600 Thousand Customers Using Smartphone Contactless Payments. Cashless's 3rd Quarter 2017 Report

The leader among banks who can boast the largest number of customers who log in using their mobile devices (this includes not only apps, but also mobile browser versions of banking websites opened on mobile phones or tablets) is, predictably, Poland's biggest retail bank - PKO BP. The company's press office stated that almost 2.3 million of the bank's customers logged in to their account via a mobile device - over 180 thousand more than in June.

Related: 66.7 Percent of Card Transactions on the Polish Market Are Contactless

Pekao is in second place - however, the bank refused to share their current number of mobile customers, therefore the data included in the table is from June. This is also the case for BGŻ BNP Paribas, but the bank promised to send in current numbers at a later time. I will update the table once they do so. In third place we have mBank with over 1.5 million customers who manage their account via their smartphones or tablets. This includes customers who logged in to their accounts from a mobile device at least once during the whole third quarter of this year. The number of customers who logged in in September is probably higher, but the company's representatives said that they can't calculate the precise number.

As for mobile only users - customers who logged in to their account exclusively via mobile devices - their number exceeded 2.1 million in September. This category is also dominated by PKO BP. The bank had almost 750 thousand mobile only customers - over 100 thousand more than in June. It's worth noticing that ING had a significant increase in the number of this type of account users (96 thousand). This allowed the bank to move up from June's fourth place to second in our September report. mBank is in third place - with the stipulation that the data is for the whole quarter. In September alone, the number of mobile only customers was probably slightly higher than the 293 thousand indicated in the table.