| 1

Castlight HealthInvestor Overview

2Q 2019

NYSE: CSLT

| 2

Safe Harbor

Statement

This presentation contains forward-looking statements regarding our trends,our strategies and the anticipated performance of our business, including ourguidance for the full year of 2019, expected ARR growth, timing of platformmigrations, timing of cash flow and non-GAAP operating break-even, costsavings efforts, impact of non-renewals, direct and channel sales momentum,our ability to add additional channel partners, future churn risk and future cashposition. These statements were made as of May 2, 2019, and reflectmanagement’s views and expectations at that time, and are subject to variousrisks, uncertainties and assumptions. If this call is replayed after May 2, 2019,the information in the call may no longer be current or accurate. We disclaimany obligation to update or revise any forward-looking statements.

We provide guidance in this presentation, but we will not provide any furtherguidance or updates on our performance during the quarter unless we do so in apublic forum. Please refer to today’s press release and the risk factors includedin the company’s filings with the Securities and Exchange Commission fordiscussion of important factors that may cause actual events or results to differmaterially from those contained in our forward-looking statements.

This presentation also includes certain non-GAAP metrics, such as non-GAAPgross profit and non-GAAP gross margin, non-GAAP operating expenses, non-GAAP operating income and non-GAAP operating loss, and non-GAAP netincome and loss per diluted share that we believe aid in the understanding ofour financial results. A reconciliation to comparable GAAP metrics, on ahistorical basis, can be found in the appendix section of this presentation.

| 3

Castlight Health

• Leading healthcare navigation platform attacking an $8B+ TAM

• SaaS model selling primarily to large self-insured US employers

• Core value proposition: reducing healthcare spending

• Significant evolution of product and go-to-market approach to drive

long-term growth and operating leverage

* Cash flow from operations

$66M in cashAs of 03/31/19

~270 Customers

ARR: $154MAs of 03/31/19

Cash flowPositive* in Q4’18

| 44

Product Evolution to Health Navigation

Care Guidance

Medical, Rx, dental comparison, spend

management, provider quality, network strategy,

care planning tools

Personalization

Predictive analytics, machine learning/ AI based models, omni-

channel, real time recommendations

Wellbeing

Challenges, content, mind/ body/wallet,

global, social, incentives, coaching,

screening

One app experience for the entire health journey

Ecosystem

Platform integration framework to enable

rapid data sharing and user experience

integration of best in breed partners

2010 Today2015 2017 2018

Individuals struggle to navigate their benefits and the healthcare system, resulting in high costs and poor outcomes

| 5

One comprehensive platform

Key Differentiators:

Personalization

Ingestion

Normalization

Data as a service

Deep Integrations

Stay healthy Manage conditionsAccess care

| 6

Delivering measurable value

Translates to 1.25%-1.75% reduction in medical costs

Up to 4x

Employee Satisfaction

70+ NPS

through steerage, as measured by Verscend*

Increase in participation in benefit programs integrated on the platform

Create a delightful benefits experience for employees***

Program Utilization

* Medical cost savings average for Castlight customers ** Represents percentage of Castlight Complete subscribers who have registered

*** NPS score reflects Castlight Complete mobile experience

Engagement

~60%HH RegistrationDriving engagement at time of launch in the Castlight platform**

Return on Investment

2x-3x

| 77

Data Aggregation & Integration at Scale

34 Medical payors10 Pharmacy Benefit Managers (PBMs)16 Dental Payors15 Behavioral / EAP programs

113 Eligibility Vendors 60 Bank integrations

100+ distinct API integrations150+ distinct single sign-on (SSO) integrations

1 billion records500 million claims15,000+ files/month

Medical Payors

PBMsDental Payors

Ecosystem Vendor

Consumer Trackers

Enrollment Vendors

Customer Vendors

User Behavior

HSA vendors

Medical ClaimsProvider DirectoryUnit PricesNarrow Networks AccumulatorsBenefit DesignInsurance card

Pharmacy ClaimsFormulariesPreventive Drug ListsPharmacy NetworksAdherence AlertsInsurance cardAccumulators

Dental ClaimsDental DirectoryPricesAnnual Accumulator Ortho Accumulator

Program Actions completedProgram completionKey results and outcomes (e.g., biometrics, HSA balance)

Fitness, sleep, or nutrition data

Member Eligibility information (social, demographic, human info) Embedded registration enrollment integration

Program Actions completedProgram completionKey results and outcomes

Search Pulse SurveysGoal selectorHealth Assessment

Account BalancesSSO

88

Current applications of

machine learning & analytics

• Clinical domain model• Quality score• Smart Match

Search Pricing

• Medical, Dental, Rx• Out of pocket cost• Advanced benefit design

Provider Directory

• Unified PD from 50+ PDs• Steerage Matching• Framework: ACO, COE, HPN

Personalization

• AI based dynamic profile• 20+ data category sources

Programs

• State of the art integration model• 200+ program integrations

Extensible Services

| 9

Personalization Engine

Data Recommendations

User Preferences

Claims

Employer

Data Partners

Gathers data from numerous sources in real-time

Builds personalized user profile that evolves over time

Engages each employee with personalized campaigns

Delivers campaigns through the best available channel

User Behaviors

Segmentation Engine Recommendation Engine

An intelligent personalization engine that matches employees to the right resources

Program

Behavior

Care Option

Predictive Content

Incentives

| 10

Castlight Complete Use Cases

| 11

Health navigation, simplified

• Integrates available benefits & user plan information & personalizes the experience

• Links with devices & tracks steps, sleep & nutrition

| 12

Health navigation, simplified

• Integrates available benefits & user plan information & personalizes the experience

• Links with devices & tracks steps, sleep & nutrition

• Delivers customized program & content recommendations

• Integrates deductible status, HSA balance & claims information

| 13

Health navigation, simplified

• Integrates available benefits & user plan information & personalizes the experience

• Links with devices & tracks steps, sleep & nutrition

• Delivers customized program & content recommendations

• Integrates deductible status, HSA balance & claims information

| 14

Personalized outreach:

• Platform identifies user as “at-risk” for back surgery

• User receives message regarding lower-cost care alternative

| 15

Personalized outreach:

• Platform identifies user as “at-risk” for back surgery

• User receives message regarding lower-cost care alternative

• App content educates & steers user:• Provides additional relevant content

• Recommends integrated program (e.g. Hinge Health)

• Curates providers by cost & quality

• Integrates plan details to help user make a better-informed decision

| 16

Personalized outreach:

• Platform identifies user as “at-risk” for back surgery

• User receives message regarding lower-cost care alternative

• App content educates & steers user:• Provides additional relevant content

• Recommends integrated program (e.g. Hinge Health)

• Curates providers by cost & quality

• Integrates plan details to help user make a better-informed decision

| 17

Comprehensive, Personalized Health Navigation

| 18

Target HR buyer within large, self-insured employers

Subscription model with three-year contracts

Continue to “land and expand”

Business Model

| 19

Hybrid go-to-market approach

Direct

Sales

Channels &

Health Plans

+ to Penetrate Early Majority Buyersfor Large, Innovator Buyers

| 20

One platform:

multiple

packages

Complete

Wellbeing Care Guidance

Direct Enterprise

e.g. Anthem Packages

Elite

Basic Care & Cost Finder

Channels

Highly configurable solutions

built off one technology stack

| 21

100%

69%

52%

21%11% 11%

31%

48%

79%89% 89%

2014 2015 2016 2017 2018 1Q 2019

Transparency

Platform

Strong Platform ARR Traction

$78M $110M $122M $163M $151M $154M

Percentage of total annualized recurring revenue (ARR)

Total ARR:

| 22

($32)

($25)

($13)

2016 2017 2018 2019 Guidance

Non-GAAP Operating Loss

Guidance Range:$0-$5mm

Profitable in Q3 & Q4’18

$ in M

illions

Proving out the business model

See appendix for a discussion of the Company’s non-GAAP metrics.

| 23

Strategic initiatives

GROWTH

SUSTAINABIL ITY

• New platform products sales

• Legacy wellbeing migrations

• Channel expansion

• Positive annual cash flow

from operations starting in

FY’19

INNOVATION• New platform features that

increase user value

| 24

Target operating model

Please see the Appendix for a discussion of the Company’s non-GAAP metrics.

(Non-GAAP, % of Revenue) Target Range

Gross Margin 70% - 75%

Sales & Marketing 20% - 24%

Research & Development 20% - 24%

General & Administrative 8% - 12%

Operating Income 20% - 25%

| 25

Thank You

| 26

Appendix

| 27

2019 Guidance

Guidance as of 05/02/19. Please see Appendix for definition of non-GAAP financial measures.

Metric Range

GAAP Revenue $153mm – $158mm

Non-GAAP Operating (Loss) $0mm – $5mm

Non-GAAP EPS $0.00 – $0.03

Weighted Avg. Shares Outstanding 145mm – 146mm

| 28

The Castlight Total Addressable Market

$8+ Billion

$5 Billion

| 29

Non-GAAP Financial MeasuresTo supplement Castlight Health’s financial statements presented in accordance with generally accepted accountingprinciples (GAAP), we also use and provide investors and others with non-GAAP measures of certain components offinancial performance, including non-GAAP gross profit and margin, non-GAAP operating expense, non-GAAP operatingloss, non-GAAP net loss and non-GAAP net loss per share. Non-GAAP gross profit and margin, non-GAAP operatingexpense, non-GAAP operating loss, and non-GAAP net loss exclude stock-based compensation, certain legal expenses,amortization of intangibles, amortization of internal-use software, and lease exit and related charges.

We believe that these non-GAAP financial measures provide useful supplemental information to investors and others,facilitate the analysis of the company’s core operating results and comparison of operating results across reporting periods,and can help enhance overall understanding of the company’s historical financial performance.

We have provided a reconciliation of each non-GAAP financial measure to the most directly comparable GAAP financialmeasure, except that we have not reconciled our non-GAAP operating loss and net loss per share guidance for the full year2019 to comparable GAAP operating loss and net loss per share guidance because we do not provide guidance for stock-based compensation expense, and capitalization and amortization of internal-use software, which are reconciling itemsbetween GAAP and non-GAAP operating loss. The factors that may impact our future stock-based compensation expense,and capitalization and amortization of internal-use software are out of our control and/or cannot be reasonably predicted,and therefore we are unable to provide such guidance without unreasonable effort. Factors include our marketcapitalization and related volatility of our stock price and our inability to project the cost or scope of internally producedsoftware.

These non-GAAP financial measures should be considered in addition to, not as a substitute for or in isolation from,measures prepared in accordance with GAAP. Further, these non-GAAP measures may differ from the non-GAAPinformation used by other companies, including peer companies, and therefore comparability may be limited. CastlightHealth encourages investors and others to review the company’s financial information in its entirety and not rely on a singlefinancial measure.

| 30

Thank you