The San Francisco-based company is expected to seek a valuation upwards of $2 billion, with Goldman Sachs (GS) tapped to lead the offering. Morgan Stanley (MS) also is expected to serve as an underwriter.

Castlight was co-founded in 2008 by Todd Park, the Athenahealth (ATHN) co-founder who later went on to create the original Healthcare.gov as chief technology officer of the U.S. Department of Health and Human Services. Since 2012 he has served as the nation’s second U.S. chief technology officer (where fixing glitches with the revised version of Healthcare.gov has become a major job requirement).

His fellow co-founders were current Castlight CEO Giovanni Colella, the former CEO of RelayHealth (acquired by McKesson) and Bryan Roberts, a partner with venture capital firm Venrock.

Current board members include Roberts, fellow Venrock partner Bob Kocher (who previously helped shape the Affordable Care Act as a member of the Obama Administration) and Facebook (FB) CFO David Ebersman (who is said to have been very supportive of Morgan Stanley’s involvement on the Castlight offering).

Castlight has raised $160 million over two rounds of venture capital funding, from Venrock, Maverick Capital, Oak Investment Partners, Morgan Stanley, U.S. Venture Partners, The Wellcome Trust and T. Rowe Price. In both 2010 and 2011 the company topped The Wall Street Journal’s rankings of the top 50 VC-backed companies (it fell out of the top 50 entirely in 2012, after the WSJ claimed that VCs had soured on healthcare).

Current Castlight customers include CVS Caremark (CVS), Kraft Foods (KRFT), Honeywell (HON) and Indiana University.

A Castlight spokeswoman declined to comment for this story.

Sign up for Dan Primack’s daily email newsletter on deals and deal-makers: GetTermSheet.com