Cross-selling new accounts or new products/services to consumers is damaging a bank’s customer loyalty as well as causing existing customers to give their financial institution a lower Net Promoter Score (NPS), according to a new study. This means that new customers should be immediately marketed an additional product.

According to a recent report released last week by nonprofit research firm BAI in its quarterly webinar titled Leading Indicators in Customer Retention, 60% of people most recently cross-sold are more likely to switch main banks in the next two years in comparison to 47% of customers who were not cross-sold.

The research showed that consumers shop for new accounts and banking products online often enough, with Millennials being the group that shops for new products and services more than any other demography.

And while cross-selling might lead the consumer to explore these new products and services, most consumers don’t become buyers. The main reason for this? Time-consuming and tedious sign-up processes.

In fact, the report found that the most commonly cited reason why cross-selling doesn’t work is because of the arduous account-opening processes. And in turn, this difficulty in signing up is also a key reason why customers tend to give banks a lower NPS score.

When it comes to account-opening or signing up for new product/service, larger banks should take a cue from challenger banks like N26 or Loot, which pay close attention to engineering its signup process to be quick and seamless by using existing data and AI technology, which automates most of the information when a customer links either their email, phone number or some sort of identification variable during signing up.

In a previous interview, Loot CEO Ollie Purdue told Bank Innovation that the U.K.-based challenger is able to acquire users for a tenth of the costs that banks do, and while maintaining an easy signup process for customers. Nic Kopp, N26 USA CEO, also told Bank Innovation that maintaining a simple interface with minimum buttons and information is a key mandate to the bank’s UX engineers.

See the entire findings released in a BAI webinar last week here.

For this quarterly research, BAI surveyed over 1,200 consumers and financial services leaders ranging from community banks to megabanks.