When BBVA Compass bit the bullet and decided to invest in a core banking system in 2011, the price seemed staggering: $360 million and more than three years to install.

Very few U.S. banks have been willing to commit so much time and expense to the basic nuts-and-bolts technology that runs all daily transactions for a bank — technology that, though in many cases 30 to 40 years old, still works perfectly well.

But now that the project is done and the new software, Accenture's Alnova, is running, the $82.9 billion-asset BBVA Compass is starting to reap results that range from the ability to offer real-time payments to the potential to offer a user experience akin to AirBnB's, offering simple tools that let customers handle transactions instantly and easily, as we've all been conditioned to expect.

"People don't want to hear that real time is the biggest technology we all need to adopt, but in a way it's as simple as that," said Manolo Sanchez, chairman and CEO of BBVA Compass, a Birmingham, Ala., unit of the Spanish giant Banco Bilbao Vizcaya Argentaria.

"If you make a Netflix or iTunes purchase, you don't want to wait two days for your purchase to come back and clear, the same way we wouldn't want ACH to take two days to go through," he said in an interview at the BAI Retail Delivery conference in Las Vegas this week.

The bank this year partnered with Dwolla, which runs a real-time payment network, to begin providing real-time payment services.

For banks to function in the modern world, "you have to reengineer things to operate in real time," Sanchez said. "It makes you work harder and write that next chapter of 'how do you protect that new part of the value chain' from a cybersecurity standpoint. But the consumer is ready for real-time banking, which we don't provide in the U.S. yet."

Most banks, including BBVA Compass until recently, still run transactions in batches rather than in real time.

To give clients the impression transactions are being executed right away, banks do memo-posting (temporary credit or debit entries, which are reversed when the batch transactions are finally posted) between their systems.

"That's a lot of work, to have transactions memo-posted to all these systems, with all these pipes connecting them," Sanchez said. And upgrades are very cumbersome under such conditions.

"Like most things in life, when you have something that's not intended to work a certain way, you can only do so many workarounds. There's a point where you're going to say, 'ok, no more workarounds. Let's get the job done,'" Sanchez said.

In addition to this motive of streamlining transactions and upgrades, the bank was also driven to modernize its technology by the need to provide a consistent experience across channels for consumers — "which is by definition real-time," Sanchez said.

"Try to connect with a 15-year-old, there's no other world but instantaneous," he said. "As that generation becomes wealthier, has bigger checking accounts and taps into more products, they're going to see the shortcomings of the system pop up," he said. "You have to have a long-term view."

The bank is rewriting its digital customer experience. It bought a user experience design firm called Spring Studio in San Francisco; it's also hired digital banking leaders like Jeff Dennes and Alex Carriles to direct such efforts.

"You're redefining convenience by letting people self-serve, letting people choose the way they want to interact with the bank in their pocket," Sanchez said.

Alongside the core banking overhaul, another major technology decision that has made BBVA Compass better able to recreate the digital experience is this: it writes all its own code.

"We don't rely on a third party, and there's a good and bad in that," Sanchez said. "You're on your own. That means you have to be progressive and stay ahead of the curve. Also, you have to deliver. But it allows you to be differentiated."

Most of the more than 12,000 banks, thrifts and credit unions in the U.S. have lookalike online banking sites and mobile banking apps. This is partly because a handful of vendors serve most of these companies. By going it alone, BBVA Compass is free to pursue its own ideas, as soon as they arise, rather than waiting for a vendor to execute when it gets around to it.

BBVA Compass also has reaped an advantage from its $117 million acquisition of the "neobank" Simple, Sanchez said. Although Simple has maintained its independence, the rest of the bank is learning from the small, creative startup behind the scenes.

"Most people say, 'why did you spend all the money you paid for Simple? Was it buying the code?' No. It's not as simple as that," Sanchez said. "All this viral marketing they do, we don't know how to do and as you know, most banks go viral on a bad note, not on a good note. In digital marketing, [outfits like Simple] are writing the next chapters."

Meanwhile, BBVA Compass is working to attract and retain top tech talent with cultural changes.

"A lot of what you need to do in addition to finding and hiring people is create an environment where they can actually contribute," Sanchez said.

"We're in the age of Wikipedia. Here we have this society that's created its own multi-language encyclopedia, without anybody ever getting paid a dime for putting that material together. This is the kind of work we can all have."

People who work for free?

"Not for free, but where they can contribute" and gain the same kind of satisfaction they would at a startup. "Some authors are calling these people cognitive surfers."

BBVA Compass is working toward a flat organizational structure in which such people can thrive.

"You want to have a purpose-driven organization; that's what we're working toward," Sanchez said. "There's an opportunity for us to be helping clients take control of their finances and go through their lives in a way that's less stressful."