Although car-sharing service Zipcar lost $2.5 million in its third quarter this year, its revenue has been steadily increasing, according to VentureBeat. Zipcar brought in $55 million in the quarter, up 46 percent from the same quarter a year ago, according to the company's most recent filing with the Securities and Exchange Commission.

Zipcar's $2.5 million quarterly loss means the company hasn't been profitable since the fourth quarter last year, when it made $1.3 million off $36 million in revenue. Most of the cost has come from fleet operations, staffing, and maintaining leases and expenses for vehicles.

Zipcar made about $58 million in 2007, about $84 million in 2008, and $131 million last year. The company has posted around 40 percent year-over-year growth each quarter this year.

The company has also recently spent money on acquisitions, most recently acquiring London car-sharing service Streetcar. Zipcar also acquired a minority stake in Spanish car-sharing service Avancar and acquired American rival Flexcar in 2007.

The company filed to go public earlier this year to raise $75 million. The funding was intended to help spin up their operations and pay off debt.