Green Dot reported a net loss in the fourth quarter as it spent money to diversify beyond its flagship prepaid card business.

The Pasadena, Calif., company lost $800,000 after earning $1 million a year earlier.

Green Dot said its operating expenses rose by about 6%, to $150.3 million. Operating revenues also rose by 6%, to $150.6 million.

The $1.6 billion-asset company, which pioneered the prepaid card, has been looking to move beyond that niche and into other consumer finance segments.

Green Dot in early November finished rolling out its mobile phone-based checking account product to Wal-Mart stores nationwide. The company said in a press release Thursday that it aims to sign up customers at an annual run rate of at least 1 million by the end of this year.

Green Dot also recently launched a separate program that will allow Wal-Mart shoppers to receive tax refunds in cash.

Those programs tied the company more closely to Wal-Mart, which owns a 4% stake in Green Dot.

In prepaid cards, Green Dot has been looking to lessen its reliance on Wal-Mart. Green Dot said Thursday that more than 1,750 new check-cashing stores started selling its cards during the fourth quarter.

Green Dot's prepaid card business showed modest growth. The number of active cards at Dec. 31 was 4.7 million, up 5% from a year earlier. Purchase volume on Green Dot cards totaled $3.5 billion, up 7%.