While some financial institutions invest in their relationships with customers, U.K. challenger bank Monzo focuses on hooking customers with community building efforts. "[The goal] is broadly to get to a stage where customers are referring their friends because they love the product and feel like they're a part of the mission -- you need to take customers away from being 'standard customers' to being advocates who are feeling like they're part of it," said Tristan Thomas, Monzo's head of marketing and community. Monzo asks customers for feedback on product launches and fees, allows them to invest in the company through equity crowdfunding rounds and holds community events across the U.K., either at Monzo offices or customer suggested venues. Its approach is based on the principle that customers will stay loyal and will refer others if they've got some kind of stake in it. Banks have traditionally relied on large-scale ad campaigns and promotions to get customers to change their providers. But U.K. customers still aren't changing their banks in droves; according to U.K. nonprofit Bacs only 4.45 million successful switches have taken place since 2013. Plus, they'll have less and less motivation to switch bank providers as more non-bank entities begin offering comparable services. The company's biggest growth driver is loyalty, with word-of-mouth referrals being the source of 80 percent of new customer growth, according to the company. The remaining 20 percent is based on a limited amount of sponsored ads on Facebook and Twitter. More than 30,000 customers participate in an online feedback forum for new products. For example, Monzo consulted with users when it was in the process of rolling out a feature that would let customers save towards pre-defined goals through savings envelopes called "pots." The product was based on a suggestion from a Monzo customer a year ago, said Thomas. Customers were then asked to suggest names for the feature, which was eventually subject to a vote. The company also engages customers for in-person beta testing of features through meetups. Separately, Monzo holds eight to 12 events per year around the U.K. featuring an invited speaker followed by a networking session over food and drinks. Like SoFi and Umpqua Bank, which host community events with the plan of turning customers into brand evangelists, Monzo's social events are part of a wider trend of event planning to engage with customers. Thomas declined to specify how much the company spends on community-based marketing, but said each event costs around "a couple of hundred pounds." Monzo also includes crowdfunding rounds that let customers become shareholders in the company. The company has held two equity crowdfunding rounds since its founding, with a $1.4 million round two years ago and a $3.5 million million round last year. Monzo, which has built a customer base of 560,000 users in just three years, has raised $153 million in equity funding, with backing from some well-heeled players including Goodwater Capital, Stripe and Michael Moritz. It's grown its customer base over five times over in a year and they've spent $1.4 billion, making it one of the U.K.'s top challenger banks. Instead of relying only on traditional advertising, Monzo's strategy is make its customers stakeholders in the business. "You can build great company through a great product -- lots of tech companies have done that -- but a much better way is to combine that with community and transparency and get the customers involved as much as possible," Thomas said. Monzo's plans to generate revenue streams are based on making Monzo a hub for a range of different banking services, many of which are offered by other companies. Thomas said Monzo is squarely interested in focusing on its checking account offering and doesn't plan to roll out other products. The company said the overseas ATM fees aren't a money maker or the company, with most revenue currently coming from overdraft loans. Plans for future profitability include turning Monzo into a financial portal, where it can refer customers to other services and companies participating would pay Monzo referral fees to participate. "In the short to medium term, [revenue] is through overdrafts, because that's a relatively straightforward way to make money; over the long term we want to build this marketplace where everything that touches your money we can help you with; perhaps we can help you switch to a cheaper energy provider," Thomas said. In a high-growth phase for the company, staying close to the customer base is the hard part. "The biggest challenge is that we're growing very fast -- our customer and employee numbers are growing fast -- we want to keep the customer focus, how we operate a transparent customer growth approach, and how we do that at scale."