What a difference a year makes. Last year, we noted that 2013 was a blockbuster year for digital health investments with almost $2 billion of private capital going into the sector. We highlighted the 10 largest deals of 2013, which ranged from $35 million on the low end to $85 million on the high end.

In 2014, digital health investment topped $4 billion, according to our friends at Rock Health, and 10 investments were valued at more than $100 million – and that number doesn't even include the digital health IPOs.

The past year saw three digital health companies go public, including our client Castlight Health, which raised $177.6 million in March in the first digital health IPO of the year. Everyday Health also made its Wall Street debut in March, raising about $100 million. HealthEquity followed in July raising $127.5 million. All three companies provide web-based services to help consumers or employers better manage health outcomes and/or the cost of care.

Three of the 10 largest private investments of the year were not conventional venture investments, including the largest deal of the year, Summit Partners' $550 million recapitalization investment in Ability Network, a developer of internet-based practice management software for hospitals and other healthcare facilities. Alignment Healthcare, which works with payers and providers to ensure continuity of care for members and patients, received a growth equity investment from General Atlantic in the amount of $125 million, and Guahao Technology, which operates Weiyi, a pair of mobile apps that connect patients and doctors, raised $100 million with a minority investment from Tencent.

Of the remaining 2014 digital health investments valued at $100 million or more, four companies (NantHealth, InVitea, Heartflow and Butterfly Networks) focus on diagnostics. By contrast, in 2013, there were no diagnostic-oriented digital health companies on my list of the 10 largest digital health investments of the year.

Top Private Digital Health Investments of 2014

Rank Company Focus Amount ($M) Date

City
1

Ability Network

Practice Management

 $550 4/7/2014 Minneapolis
2

Privia Health

Practice management and population health

 $400 9/16/2014 Arlington
3

NantHealth

Diagnostic clinical platform that incorporates genetic information

 $320 10/2/2014 Culver City
4

Flatiron Health

Real-time, cloud-based data platform focused on the oncology market

 $130 5/7/2014 New York City
5

Alignment Healthcare

Continuous care programs

 $125 4/29/2014 Irvine
6

InVitae

Genetic information company specializing in genetic diagnosis of hereditary diseases

 $120 10/13/2014 San Francisco
7

Proteus Digital Health

FDA-cleared ingestible sensor

 $120 6/2/2014 Redwood City
8

HeartFlow

Non-invasive system for the diagnosis of coronary artery disease

 $104.7 2/27/2014 Redwood City 
9

Guahao Technology

Weiyi, a pair of mobile apps connecting patients and doctors

 $100 10/13/2014 Shanghai (China)
10

Butterfly Network

System for diagnostic imaging that combines a handheld device with a cloud-based analytics service

 $100 11/3/2014 Guilford (Connecticut)

The growing significance of the digital health sector was not lost on attendees at J.P. Morgan's Healthcare Conference in January. The contingent of digital health companies at the biotech investor meeting was larger and more visible this year than in years past. Prolific digital health investor Bryan Roberts of Venrock and 23andMe's CEO Anne Wojcicki drew standing-room only crowds.