The iPhone app was developed by Citi FinTech, a specialist unit charged with using agile development methodologies to accelerate speed to market for next-generation mobile banking services.

Stephen Bird, CEO, global consumer banking at Citi, says the new product "demonstrates the power and potential of our new agile operating model, a spearhead to leading what's next for our clients and for Citi".

The app was tested with 2500 clients over a five-month period to refine design and prioritise development, with new features added in a series of two-week development sprints. Built using an open architecture incorporating portable APIs, the product can be modified in real time and adjusted for different client needs and markets, says Bird.

Initially tailored for US Citigold clients, the app offers a choice of five methods of authentication, including fingerprint, voice, facial recognition and PIN, in additional to a traditional password.

Once logged in, users can make global transfers to linked current accounts using just an account number, as well as buy and sell equities, ETFs and mutual funds. In the days ahead, Citigold clients will additionally be able to open a new brokerage account in-app.

The app also comes wrapped with a 'Click-to-call' facility, offering 24-hour access to relationship managers and financial advisors for more complex dealings.

"We set out to solve for our clients' more complex financial and investment needs first, which is why many new features are tailored to Citigold clients," says Yolande Piazza, chief operating officer at Citi FinTech. "Utilising an agile operating model, the team was able to design, build and deliver in months what previously would have taken years to do. We co-created this product with our clients and deeply appreciate their time and input. We will monitor engagement and feedback, improve in real-time and then expand to more clients and markets."