In recent years a profusion of fintech companies have emerged as challengers to traditional banks. While some offer themselves as dynamic, online alternatives to traditional banking, others are taking charge of specific services that used to be part of a bank's remit, such as international transfers or electronic payments.

Targeting their services to specific segments can look like what mobile-only bank Starling has done this month, following up on their current account with a business account specifically for small entrepreneurs and sole traders. Their product promises to be much quicker to set up than the business accounts of established banks. Honing in on the specific needs of small businesses, who want less admin and more flexibility, this is likely to draw business away from.

Many new Fintechs have also been gaining popularity by targeting customers more personally. They present themselves as being on the side of the consumer, passing on the savings made by their more agile, low-cost online services, and championing consumer rights by calling out and cutting the higher fees charged by large banks. There are many examples where this marketing is working a treat.

With personalised rewards, such as tailored discounts or making individual suggestions on how to better manage their money, these new financial service providers do their utmost to build a personal relationship with each customer, often at the expense of established banks. This has been a powerful formula for these new businesses to win custom from the more established players in the industry.

However, despite the success of the Fintech approach, established banks still retain the balance of power – for the time being. Deloitte has estimated that peer-to-peer lending, for instance, represents only 0.96% of the consumer lending market at present. One of the main advantages large established banks have is exactly that – they are large and established.

Despite lingering trust issues from the financial crisis ten years ago, established banks' reputations are by-and-large well-known and respected, and seem more trustworthy than new online brands that consumers are less familiar with.

Their size and history, perhaps more crucially, means that they enjoy a large customer base from which to generate revenue – and this customer base currently doesn't move much. The Competition and Markets Authority has found that each year only 3% of personal account customers and 4% of business account holders switch bank accounts.

But this isn't necessarily because customers are happy with the service they have been getting. A recent Which? survey reported that the largest banks, including RBS, HSBC, Natwest and Barclays, are rated the worst in the UK for customer service. So it would appear that the reason customers do not tend to switch bank accounts is not purely out of loyalty or satisfaction, but the difficulty of moving, and the lack of other visible options.

This is likely to change in the wake of the Open Banking Initiative, with the second Payment Services Directive (PSD2) coming into force in January 2018. Under these regulations, banks will be forced to share their customer account data with other companies upon customers' requests, and open up the back end of their systems to third-party developers.

Other businesses will be able to make payments from accounts directly, without having to go through the bank or payment services companies, so switching money around electronically will be much easier. It will also allow aggregators to siphon customers' data from various accounts onto one platform, enabling them to make recommendations to customers as to how they can switch providers to save money and get better rewards.

With the variety of offers more visible and switching accounts and payment providers made much easier after Open Banking, the financial services market could become much more fluid – perhaps a lot more like the retail industry, with customers switching around their custom and trying a variety of brands and products, sometimes deciding on a few favourite providers which match their lifestyle needs.

Due to the low entry barriers of retail, customers are continually buying from a range of brands, and switching around their brand loyalties. In e-commerce, for instance, roughly 63% of customers will make only one purchase from a retailer. To combat this, retailers employ a variety of retention strategies to keep consumers coming back to buy more, building a personalised relationship with people who have bought from them.

Offers such as birthday promotions, rewards for loyalty, and discounts tailored to each customer's taste open up a flow of mutually beneficial communication with each customer, conversing with them in a personalised, emotionally-intelligent way. The key is to offer a real value return that will keep them coming back to that brand. As well as improving customer service in-branch and on the phone, traditional banks will have much to learn from retailers' marketing strategies, if they are to keep up with the personalisation of rival Fintech services.

The key to this kind of communication is to develop an interaction that doesn't annoy the customer but offers them a real value exchange that appeals to them personally. The best way to ascertain what works best for each customer is by making the most of the large amounts of data about them that large banks already have.

Until January 2018, established banks still have exclusive access to data on their customers. But after PSD2 this advantage will be opened up to a variety of competitors, whose personalised services represent a very tangible threat to established financial providers. To stay ahead of the game, they will need to make the most of this advantage to develop a spectrum of marketing strategies that, while increasing turnover, make each customer feel that they are getting real value from their relationship with the bank. Established providers will have to think like retailers, and fight harder to keep hold of their existing customers.

Pini Yakuel is the CEO of Optimove.