San Francisco-based start-up Castlight Health, whose mission is to shed light on healthcare pricing, has raised $100 million in Series D funding. This new round of investment brings its total funding to $181 million.

The funding includes participation from two major unnamed mutual funds, as well as T. Rowe Price, Redmile Group and previous investors.

The previous round of funding included Morgan Stanley Investment Management, and the Wellcome Trust, U.S. Venture Partners, as well as Cleveland Clinic. The Series C round also included Maverick Capital, Oak Investment Partners and Venrock.

Castlight provides employers and their employees easy access to typically hard-to-find cost and quality data on common medical procedures and services

“As the recognized market leader, we know the vast potential for our health care transparency solutions,” said Giovanni Colella, MD, co-founder and CEO of the company. “Castlight Health has achieved tremendous growth in a short period of time and currently maintains a strong cash position. By expanding our funding, we can respond to the growing demand for our solutions, seize major market opportunities, increase the breadth of our offerings and extend our reach.

Colella co-founded Castlight in 2008, along with Todd Park, who now serves as chief technology officer of the United States. Prior to founding Castlight, Giovanni was founder, president and CEO of RelayHealth, which was acquired by McKesson.

Colela points to recent research that shows health insurance premiums in the United States increased by an average of 8.0 percent between 2000 and 2009, whereas average household income rose by an average of only 2.1 percent.

To combat this increase, he says, many employers are asking employees to pay a larger portion of their healthcare. Without the proper tools, employees are forced to make decisions based on limited information and little understanding of options, ultimately resulting in lower quality, higher costs and a decline in overall satisfaction.

“The healthcare industry is in dire need of innovation,” said Bryan Roberts, partner at Venrock and co-founder and chairman of Castlight Health. “Castlight has the opportunity to dramatically improve the efficiency of the U.S. healthcare system, providing employers and consumers with the information required to make good cost and quality healthcare decisions. Over the last two years, Castlight Health has created the unique products to drive customer traction and ROI, which sets them on a terrific growth trajectory over the next several years.”
 
“We were attracted to Castlight Health's strong management team and the leadership position it has already established in the market,” said Graham McPhail of T. Rowe Price. “Castlight appears poised to dominate the segment and transform how users consume health care.”
 
“Traditionally, individuals have been very passive participants in managing their health care, as they have no insight into the cost and quality of the services,” said Toby Cosgrove, MD, CEO of the Cleveland Clinic. “Transparency in health care can lead to higher-quality, lower-cost healthcare, as well as more consumer engagement. With its innovative technology and strong understanding of the market, Castlight is well positioned to make health care transparency a reality and transform how users make decisions.”
 
Among Castlight Health customers are Allegis Group, Honeywell, Life Technologies and Regis Corporation.