British banking startup OakNorth is growing its consumer deposits base through a partnership with robo-adviser Moneybox in an effort to offer a savings account geared at millennials.

The Cash Lifetime ISA, available via the Moneybox app, has an interest rate of 1.4%, which OakNorth and Moneybox claim is market-leading. The account is meant to help customers who are saving for their first home or retirement.

Amir Nooriala, chief strategy officer at OakNorth, said the U.K. government’s introduction of the Lifetime ISA, which includes a 25% bonus of up to £1,000 ($1,260) per year, was a welcome step for millennials seeking to climb the property ladder, although few banks offer it. “You can only put in £4,000 per year and the value in each account is normally quite low, so you need to collect a whole load of accounts,” he noted. “Also, ISAs as a product are still a somewhat paper-based product, so you can’t fully automate them.” By combining Moneybox’s and OakNorth’s technology, the companies believe they can streamline the account-opening process, “even if it’s paper-involved,” and build momentum around the market.

OakNorth’s collaboration with Moneybox is the latest partnership to extend its reach to new customers. Since March, the banking startup has powered similar tax-efficient savings accounts for U.K. challenger bank Monzo and its roughly 2 million customers.

Overall, Nooriala said OakNorth, which launched its platform in September 2015, offers a range of savings products that have helped the bank reel in billions of pounds in deposits from about 50,000 customers. The digital-only bank typically has targeted high-net-worth individuals for deposits that fuel its ability to lend to small and medium-sized businesses, but that approach is changing, he noted. OakNorth realized that by targeting rate-seekers who actively comb the internet for the best rates, it was missing out on a large swath of the potential market, he explained.

OakNorth is not a transactional bank, and the reality is most consumers prefer to go to a single app to handle all of their investments and day-to-day transactions, Nooriala said. Partnering with fintechs which provide transactional services is the most efficient way to work around that problem and reach more customers, he explained. In return, the fintechs get to provide their customers access to savings account products that would be too high of a cost for them to provide otherwise, he added.

OakNorth’s focus on high-net-worth individuals has meant it only needs tens of thousands of customers with tens of thousands of pounds of deposits to raise billions in savings, Nooriala noted. On the other side of the spectrum, Monzo’s millions of users might only have hundreds of pounds of deposits each, while Moneybox users, who number in the hundreds of thousands, might have balances in the low thousands.

Also see: U.K. Fintech Lender OakNorth Makes Way to the U.S.

OakNorth has grown rapidly since raising $440 million from investors, including SoftBank, in a February funding round that valued the company at $2.8 billion. Staffing levels have nearly doubled from just below 300 in February to 520 today, as the company adds software developers, credit experts and product designers at a pace of about 15 per week. Unlike most challenger banks, OakNorth has been profitable since 2018.

Meanwhile, OakNorth also announced today that it signed a five-year deal to provide its white-label credit analysis and monitoring platform to Dutch commercial lender NIBC Bank. The deal with NIBC, based in the Hague, is the first enterprise-wide agreement to be announced between OakNorth and a bank, as the firm works to monetize its proprietary software. OakNorth said nine banks, including two in the U.S., currently are using the platform. Financial details of the deal were not disclosed.