This former Goldman Sachs partner is helping the start-ups that are killing the banks right now

Four-year-old London-based foreign exchange platform Kantox just scored a very important investor - Patrick de Nonneville.

De Nonneville was until January a top European executive at Goldman Sachs but left the pinnacle of traditional finance to join the booming world of FinTech.

De Nonneville, formerly co-head of European Interest Rate Products for Goldman, joined online French business loan start-up Lendix as its COO at the start of the year after more than seven years at Goldman.

He's now taken part in an $11 million funding round announced today in Kantox, a foreign exchange platform headquartered in London. He's also joining the start-ups board.

Both Lendix and Kantox are part of a new wave of businesses using technology to make banking faster, cheaper and easier. In the process they're also terrifying traditional banks by eating into their business.

"There's a big realisation inside the financial industry that the changes which are being brought about for big financial companies have opened up a lot of opportunities outside of the main banks," de Nonneville told Business Insider.

"I don't think these big banks are bad at innovating. [But] It's very, very different doing inside a very big organisation, which can have a different focus to the one that you want to have, to doing it with a smaller, very driven team."

He added: "I'm not the only one to make this kind of move. The CFO of Morgan Stanley went to Google."

The current wave of FinTech companies could transform banking in this country in the same way that the 'Big Bang' did in the 1980s.

"There are opportunities to redesign some businesses completely from the ground up," de Nonneville told us. He sees banking moving towards an "app ecosystems" like we have on our phones.

He told Business Insider: "You go on your phone and you've got an app that tells you the bus times. What Kantox has built is an app that does a few things extremely well and is very easy to use."

'The banking scandals have helped us'

Kantox's platform matches up businesses that want to transfer money into different currencies with other companies making similar trades in the reserve direction. By letting them trade directly with each other and cutting out traditional middle men it reduces the fees companies have to pay.

The start-up has over 1,500 customers and in February announced it has processed over $1 billion worth of transactions. CEO Philippe Gelis told Business Insider that the figure has already risen to $1.5 billion and Kantox expects to hit the $2 billion mark by October.

He said the string of scandals to come out of the banking industry, including recent massive fines for foreign exchange rigging, have helped Kantox.

"From 2008, all the banking scandals have helped us a lot in the sense that clients consider that banks are suppliers more than partners," Gelis told Business Insider.

"Every time we try and push for transparency and every time there is this type of scandal, clients and customers believe more and more our transparency philosophy and feel more and more comfortable using alternative finance like us."

But both Gelis and de Nonneville think the future will see FinTech firms working with big banks rather than trying to beat them. Gelis told Business Insider: "Here are Kantox we don't like bank bashing. We're convinced that FinTech in the future will be all about competition and cooperation."