Yodlee Inc. filed to make an initial public offering. Even though it has been losing money for years on end.

Yodlee was founded in 1999. It has been profitable only once, in 2010. According to Yodlee, the company’s accumulated deficit was about $351 million at the end of last quarter.

In all the years, Yodlee has never broken through. While the company has been on a growth spurt since the credit crisis, its revenue last year was $70.2 million; that’s not even Square territory, which reportedly posted revenue north of $100 million last year — and Square was founded in 2009. Sure, many a tech company goes public showing net losses, but how many were founded in 1999?

Yodlee started as an online personal financial management application, but soon ran into the brick wall known as bank data protocols. It has evolved regularly ever since, and today makes most of its money by acting as the data middleman between banks and banking applications, such as Kabbage and LearnVest.

The company’s recent +20% revenue growth has been countered by some noteworthy expense trends at Yodlee. Yodlee employed 776 at the end of last quarter, up +20% from the end of 2011. R&D is a big spend at 25% of total expenses. But spending on sales and marketing and on G&A are currently increasing most at the company — up 26% and 37%, respectively.

Warburg Pincus, the financial services-focused private equity firm, owns 37% of Yodlee.

I’ve been engaged in the financial services market since 1993, and Yodlee has always been something of a mystery. The business model changed regularly over the years, and I can’t say I knew who the chief executive officer was at any given time. Indeed, the current CEO, Anil Arora, is about as low-profile as a vendor CEO can get. He spoke at Money 2020 last year in one of his first public appearances (see below). He became CEO in 2000.

The last fintech company to go public was Q2 Holdings Inc., which IPOed in late March. Its stock price is down about 6% since then.