A cheerful, unbankerly clamor greets visitors to Rise, Barclays' new space for startups on the second floor of the Castro building in Manhattan's chic Flatiron district.

Dozens of groups of people talk, work and occasionally laugh, at long tables, on cozy pillow-strewn couches and perched on stools at high counters in the snack areas. All the tables have little baskets of snacks like peaches or protein bars every few feet, like a health-conscious Halloween party. The bright lighting, primary colors and pale wood floors make you forget it's raining outside.

Derek White, chief design and digital officer of Barclays, gave a tour of the grounds last week. It didn't take long. For now, Rise occupies one roughly 11,000-square-foot floor of the building (a floor above is being renovated for a future expansion). With the open floor plan, you can pretty much see everything by turning around. At one end, employees of 11 startups work alongside bankers who help them understand Barclays' tech needs. (The startups were selected from 530 candidates.) At the other end is an event space anyone can use for free, as long as the gathering fits with Barclays' mission of "furthering and connecting the fintech ecosystem."

"We're trying to do what banks used to do: be the center of the community," White said.

Barclays is hardly the only large bank to host an accelerator for young fintech companies. What's unique about the British bank's effort is its scope, size and depth.

For one thing, the New York accelerator, which opened last week, is one in a series — Barclays has similar facilities in London and Manchester, England, and plans to open others in Tel Aviv, Johannesburg, Mumbai and Lithuania. (Barclays is the largest employer in the Baltic state, with almost 1,500 employees in its tech center, in spite of not having a retail bank there. "The quality of the [tech] talent is amazing," White said.)

Bob Gach, managing director of Accenture Strategy Capital Markets, called Barclays' program complementary to what other financial services firms are doing. Where some initiatives, like the New York FinTech Innovation Lab run by Accenture and the Partnership Fund for New York City, focus on helping fintech companies explore their cases and pain points for the industry, Barclays' accelerator helps drive those ideas through to the pilot stage, he said.

"Any model or program that helps startups truly understand the pain points and regulatory and technological complexities that banks contend with will be beneficial for both the firms as well as the startups," Gach said.

A unique characteristic of Barclays' program is the degree of commitment to these startups.

At the end of its first 90-day accelerator program in London, for instance, the bank signed contracts with three of the graduating startups. This year it has agreements in place with seven of the ten graduate companies.

"The most valuable thing we can do for these companies is become a customer," White said.

Large financial institutions have a variety of motives for setting up spaces in which startups can work and collaborate with each other and with bank executives: to understand disruptive technologies being created outside banking; to support struggling young fintech companies; to obtain advice from entrepreneurs on how to modernize banking; to get ideas and help in creating customer-friendly apps; to locate sources of tech talent; and simply to be part of the conversation about the future of fintech.

Wells Fargo, Deutsche Bank and BBVA Compass have such programs. Some banks sponsor or support independent incubators; for instance, Barclays, HSBC, Lloyds, and Royal Bank of Scotland all support Level39 in London. (In New York, Barclays works with an outfit called Techstars.) Bank of America sponsors a financial-services technology incubator at Packard Place in Charlotte, N.C., and it supports similar efforts in New York and London. Dozens of large banks work with the Fintech Innovation Lab hosted by Accenture in New York, London and Hong Kong every year.

White, who oversees Barclays' designers and developers as well as its accelerators, is fond of saying he's bringing empty pockets (startup entrepreneurs) together with deep ones (large banks and corporations).

"The magic that comes of bringing them together I refer to as true reciprocity, where large corporates are benefitting from the emerging technology startups are creating," he said.

One graduate of the London program, Dopay, determined that 90% of people in Egypt don't have a bank account and make less than $6,000 a year. The startup is using its cloud-based payroll solution to create a bank for these people. White, who used to run Barclays' retail bank in Egypt, connected Dopay with bank executives there.

"They're now using our bank charter in Egypt. We signed an agreement with the government and in the first phase, they'll be offering up to 500,000 customers a bank for the unbanked," White said.

In London, Barclays, Central Working and Techstars created a co-working space that any type of startup could use — an aquaponics company, a chip manufacturer and robotics companies all use it. Microsoft Ventures also uses the space, a fact that White gloats over.

"One of the world's leading tech companies decided to put their most successful ventures unit in a space a bank created," White said.

How does a bank explain to shareholders that it's paying rent for an aquaponics company?

"Because of the value it creates," White said. "The creativity and cross-fertilization across industries is powerful." Shareholders "see the pace at which this is fundamentally changing Barclays, a 325-year-old company."

Still, the No. 1 question bankers ask when they visit one of Barclays' accelerators is, how does it provide a return on investment?

White offers his own version of this calculation. "Every cohort [group of accelerator applicants] that comes in is 550 startups telling us what our future should be," he said. Each startup has about four people. "That gives you a view into future talent, disruptors and creators in the industry," White said. It equates to millions of pounds' worth of entrepreneurial advice, an alternative to working with the big consultants who tend to recycle other banks' ideas.

"And by providing a platform, we get invited into conversations because we're viewed as shapers, not as sponsors," White said. For example, a year ago, the Bitcoin community converged in London for an event using Barclays' space and online platform, thinkrise.com. Then, "they started to invite us to their events — the anarchists were inviting the bankers. And you start to have very different conversations when you're an invite rather than sponsoring with eight big letters on a wall."

Barclays is hoping to turn its innovation work into a line of business. It has begun offering innovation services to corporate clients.

"Some of our largest clients are now asking us to run innovation as a service, or innovation sessions with them as they've seen the power of the platform we've created," White said. The bank offers hackathons and accelerator co-hosting, for instance. Starbucks and Microsoft have used Barclays' London accelerator space to co-host startups.

Some predict fintech startups will "unbundle" banking — take over and transform the best pieces of the business, relegating banks to utilities in the background. White says it's better to ride the wave than get caught in the undertow.

"In order for banks not to become the next Blockbuster, we need to embrace this and rapidly become a technology company that does financial services," he said.

"We can choose to embrace it, create the next startup that's going to be the next company for Barclays, we can partner, we can create it ourselves organically … we can buy in or we can choose to sit on sidelines and believe disruption is not going to happen."