Q1 2014 Earnings Results. Conference Call and Webcast. April 22, 2014

Q1 2014 Earnings Results Conference Call and Webcast April 22, 2014

Forward-looking Statements The projected financial results presented in the following slides represent management's estimates of Gilead s future financial results. Gilead cautions readers that forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially. These risks and uncertainties include: Gilead's ability to achieve its anticipated full year 2014 financial results; Gilead's ability to sustain growth in revenues for its antiviral, cardiovascular and respiratory programs; availability of funding for state AIDS Drug Assistance Programs (ADAPs); continued fluctuations in ADAP purchases driven by federal and state grant cycles which may not mirror patient demand and may cause fluctuations in Gilead's earnings; the possibility of unfavorable results from clinical trials involving sofosbuvir (SOF), including in combination with other product candidates such as ledipasvir (LDV); the levels of inventory held by wholesalers and retailers which may cause fluctuations in Gilead's earnings; Gilead's ability to submit NDAs for new product candidates in the timelines currently anticipated; Gilead's ability to receive regulatory approvals in a timely manner or at all, for new and current products, including the single tablet regimen of LDV/SOF and idelalisib; Gilead's ability to successfully commercialize its products, including Sovaldi, Stribild, Vitekta and Tybost; the risk that estimates of patients with HCV or anticipated patient demand may not be accurate; Gilead's ability to successfully develop its respiratory, cardiovascular and oncology/inflammation programs; safety and efficacy data from clinical studies may not warrant further development of Gilead's product candidates; the potential for additional austerity measures in European countries that may increase the amount of discount required on Gilead's products; fluctuations in the foreign exchange rate of the U.S. dollar that may cause an unfavorable foreign currency exchange impact on Gilead's future revenues and pre-tax earnings; and other risks identified from time to time in Gilead's reports filed with the U.S. Securities and Exchange Commission (SEC). In addition, Gilead makes estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses and related disclosures. Gilead bases its estimates on historical experience and on various other market specific and other relevant assumptions that it believes to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ significantly from these estimates. You are urged to consider statements that include the words may, will, would, could, should, might, believes, estimates, projects, potential, expects, plans, anticipates, intends, continues, forecast, designed, goal, or the negative of those words or other comparable words to be uncertain and forward-looking. Gilead directs readers to its press releases, Annual Report on Form 10-K for the year ended December 31, 2013 and other subsequent disclosure documents filed with the SEC. Gilead claims the protection of the Safe Harbor contained in the Private Securities Litigation Reform Act of 1995 for forward-looking statements. All forward-looking statements are based on information currently available to Gilead, and Gilead assumes no obligation to update any such forward-looking statements. This presentation includes GAAP and non-gaap financial measures, a complete reconciliation between these two measures is available on the Company s website at www.gilead.com within the investor section. Management believes this non-gaap information is useful for investors, when considered in conjunction with Gilead s GAAP financial statements, because management uses such information internally for its operating, budgeting and financial planning purposes. Non-GAAP information is not prepared under a comprehensive set of accounting rules and should only be used to supplement an understanding of Gilead s operating results as reported under U.S. GAAP. 2

Q1 2014 Earnings Call Agenda Introduction Commentary Patrick O Brien, VP, Investor Relations John Martin, Chairman and CEO Paul Carter, EVP, Commercial Operations Robin Washington, EVP and CFO Q&A Also: John Milligan, President and COO Norbert Bischofberger, EVP, R&D and CSO 3

John C. Martin, Ph.D. Chairman and CEO April 22, 2014

Q1 2014 Corporate Highlights Corporate - Record product sales of $4.9 billion for the quarter ended March 31, 2014 up 104% year over year HCV Highlights - Marketing authorization and launch of Sovaldi in Europe - Submitted NDA for the single tablet regimen (STR) of LDV/SOF in GT 1 patients with PDUFA date of October 10, 2014 - Announced validation and assessment of Marketing Authorisation Application for the STR of LDV/SOF Oncology Highlights - Announced priority review and PDUFA date of August 6, 2014 for idelalisib in CLL - Announced standard review and PDUFA date of September 11, 2014 for idelalisib in inhl 5

Pipeline Product Candidates HIV Cobicistat (PK enhancer) Elvitegravir (integrase inhibitor) STR of EVG/cobicistat/FTC/TAF STR of DRV/cobicistat/FTC/TAF Phase 1 2 3 EU Approved as Tybost; U.S. Regulatory Submission EU Approved as Vitekta; U.S. Regulatory Submission Regulatory Submissions Liver Diseases HCV STR of LDV/SOF (NS5A inhibitor/nucleotide NS5B inhibitor) FDC of SOF/GS-5816 (pan-genotypic NS5B/NS5A inhibitors) GS-9669 (non-nuc NS5B site 2 polymerase inhibitor) GS-9451 (NS3 protease inhibitor) GS-9857 (pan-genotypic NS3 protease inhibitor) U.S. and European Regulatory Submissions HBV TAF (nucleotide reverse transcriptase inhibitor) GS-4774 (Tarmogen T cell immunity stimulator) - HBV GS-9620 (TLR-7 agonist) - HBV/HCV Other Simtuzumab (monoclonal antibody) - Liver Fibrosis Simtuzumab (monoclonal antibody) - NASH Simtuzumab (monoclonal antibody) - Primary Sclerosing Cholangitis GS-5745 (MMP9 mab inhibitor) - Ulcerative Colitis GS-6673 (ALDH-2 inhibitor) - Drug Addiction 6

Pipeline Product Candidates (cont d) Oncology/Inflammation Idelalisib (PI3K delta inhibitor) - inhl Idelalisib (PI3K delta inhibitor) - CLL Momelotinib (JAK inhibitor) - Myelofibrosis Momelotinib (JAK inhibitor) - Pancreatic Cancer Simtuzumab (monoclonal antibody) - Pancreatic Cancer Simtuzumab (monoclonal antibody) - Myelofibrosis Simtuzumab (monoclonal antibody) - Colorectal Cancer GS-9973 (Syk inhibitor) - Hematological Malignancies GS-5745 (MMP9 mab inhibitor) - Solid Tumors Cardiovascular Ranolazine (late sodium current inhibitor) - Incomplete Revascularization Post PCI Ranolazine (late sodium current inhibitor) - CAD in Type 2 Diabetes Mellitus Ranolazine (late sodium current inhibitor) - Paroxysmal Atrial Fibrillation GS-6615 (late sodium current inhibitor) - LQT-3 Syndrome GS-6615 (late sodium current inhibitor) - Hypertrophic Cardiomyopathy GS-6615 (late sodium current inhibitor) - Ventricular Tachycardia/Ventricular Fibrillation GS-4997 (ASK-1 inhibitor) - Diabetic Nephropathy Respiratory GS-5806 (fusion inhibitor) - Respiratory Syncytial Virus Simtuzumab (monoclonal antibody) - IPF Phase 1 2 3 U.S. and European Regulatory Submissions U.S. and European Regulatory Submissions Regulatory Submissions 7

Sofosbuvir Regulatory Filing in Japan Anticipated regulatory submission to PMDA by mid-2014 Filing will be supported by results from SOF Phase 3 study in GT 2 (SOF + RBV dosed for 12 weeks) HCV infected patients Achieved overall SVR12 97% (n=148/153) Achieved SVR12 98% (n=88/90) in treatment naïve patients Achieved SVR12 95% (n=60/63) in treatment experienced patients 8

New England Journal of Medicine: Once-Daily STR of LDV/SOF for HCV ION-1: With or without ribavirin for 12 or 24 weeks was highly effective in previously untreated patients with HCV GT 1 infection ION-2: High rates of SVR among patients with HCV GT 1 infection who had not had a sustained virologic response to prior interferon based treatment ION-3: 8 weeks associated with a high rate of SVR among previously untreated patients with HCV GT 1 infection without cirrhosis No additional benefit was associated with the inclusion of ribavirin in the regimen or with extension of the duration of treatment to 12 weeks Source: NEJM April 11, 2014. 9

Study 102 Phase 2 Study: SOF/GS-5816 in GT 1-6 HCV Treatment-Naïve (N = 144) Study Weeks SOF 400 mg QD / GS-5816 25 mg QD (GT 1 w/o cirrhosis) 12 N = 77 SOF 400 mg QD / GS-5816 25 mg QD (GT 3 w/o cirrhosis) SVR12: 94.8% (73/77) SOF 400 mg QD / GS-5816 25 mg QD (GT 2, 4, 5, or 6 w/o cirrhosis) SOF 400 mg QD / GS-5816 100 mg QD (GT 1 w/o cirrhosis) N = 77 SOF 400 mg QD / GS-5816 100 mg QD (GT 3 w/o cirrhosis) SVR12: 96.1% (74/77) SOF 400 mg QD / GS-5816 100 mg QD (GT 2, 4, 5, or 6 w/o cirrhosis) 10

TAF STR Phase 3 Studies in Treatment-Naïve HIV-1 Patients Studies 104 (n=866) and 111 (n=868): Randomized 1:1 Treatment Arm 1 (n=420) STR TAF 10mg/EVG 150 mg/cobi 150 mg/ FTC 200 mg + placebo-to-match Stribild Treatment Arm 2 (n=420) Stribild + placebo-to-match STR EVG 150 mg/ COBI 150 mg/ftc200 mg/taf 10 mg QD 48 weeks 48 weeks Randomization stratified by: HIV-1 RNA level ( 100,000 c/ml, > 100,000 to 400,000 c/ml or >400,000 c/ml), CD4 count (<50 cells/µl, 50-199 cells/µ or 200 cells/µl) and region (US vs. Ex-US at screening). 11

TAF STR Phase 3 Studies Ongoing to Address Several Populations Adult Switch Patients (n = ~1,500) Multiple studies could support a broad label at launch Adults with Mild/Moderate Renal Impairment (n = ~200 Tx-Naïve or Tx-Exp) Adults on Failing Treatment (n = ~100) EVG/COBI/FTC/TAF STR Adults on Complex, Multi-Pill Regimen (n = ~170) Adolescents (n = ~50 Tx-Naïve) Potential to replace Stribild. 12

Idelalisib Regulatory Filings Relapsed-refractory CLL U.S. NDA submitted on December 6, 2013 (PDUFA date August 6, 2014) o Following recommendation by independent Data Monitoring Committee, Phase 3 Study 116 stopped early due to positive risk-benefit Received Breakthrough Therapy designation and priority review Submitted MAA in Europe on October 28, 2013 Relapsed-refractory inhl U.S. NDA submitted on September 11, 2013 based on positive Phase 2 results (PDUFA date September 11, 2014) o Overall response rate 54% o o Progression free survival 11.4 months Median duration of response 11.9 months Submitted MAA in Europe on October 28, 2013 13

Significant Pipeline Milestones Anticipated in 2014 HIV TAF Elvitegravir Cobicistat Q1 14 Q2 14 Q2 14 Q4 14 Q2 14 Q4 14 Q1 14 Q4 14 Data from Phase 2 study: DRV/C/F/TAF Initiate Phase 3 study: FTC/TAF versus FTC/TDF (Truvada) Complete enrollment of additional Phase 3 studies for switch, renal impairment, adolescent, and treatment-experienced Top-line data from Phase 3 treatment naïve studies Resubmitted U.S. NDA FDA approval (PDUFA October 4) Resubmitted U.S. NDA FDA approval (PDUFA October 3) Stribild Q4 14 Complete switch studies (NNRTI and PI/r) 14

Significant Pipeline Milestones Anticipated in 2014 (Continued) Liver Disease Sofosbuvir Ledipasvir/ Sofosbuvir Q1 14 Q3 14 Q1 14 Q1 14 Q1 14 Q4 14 Q4 14 European EMA approved (January 17) Japan Regulatory submission for SOF + RBV in GT-2 patients Filed U.S. NDA for the STR of LDV/SOF Initiated Phase 3, ION-4 study in HIV/HCV co-infected patients European Regulatory submission for the STR of LDV/SOF FDA approval of STR of LDV/SOF (PDUFA October 10) in GT 1 HCV patients Japan Regulatory submission for the STR of LDV/SOF in GT 1 patients Sofosbuvir/ GS-5816 Q3 14 Initiate Phase 3 HCV studies TAF 2H 14 Complete enrollment in Phase 3 HBV studies GS-4774 Q1 14 Completed enrollment of Phase 2 study in HBV GS-9620 Q3 14 Initiate Phase 2 study in HBV patients Simtuzumab Q3 14 Q3 14 Complete enrollment of Phase 2 studies in NASH Complete enrollment of Phase 2 study in PSC 15

Significant Pipeline Milestones Anticipated in 2014 (Continued) Oncology/Inflammation Idelalisib Momelotinib Simtuzumab GS-9973 Cardiovascular Q1 14 Q2 14 Q3 14 Q3 14 2H 14 Q2 14 Q2 14 Q1 14 Q1 14 Q4 14 2H 14 2H 14 Initiated Phase 3 study for Idelalisib use in frontline CLL Initiate Phase 3 studies for Idelalisib use in frontline inhl FDA approval (PDUFA August 6) in CLL FDA (PDUFA September 11) and EMA approval in inhl EMA approval in CLL Initiated Phase 3 study in Myelofibrosis in patients previously treated with Ruxolitinib Initiate Phase 2 study in frontline Pancreatic Cancer Completed enrollment in Phase 2 study in Colorectal Cancer Completed enrollment in Phase 2 study in Myelofibrosis Top-line Phase 2 data in Colorectal Cancer Initiate Phase 2 study in inhl Initiate Phase 2 study in CLL Letairis Q3 14 Top-line data from AMBITION study GS-6615 Q3 14 Initiate Phase 2 studies in cardiovascular conditions GS-4997 Q3 14 Initiate Phase 2 study in diabetic nephropathy 16

Paul Carter EVP, Commercial Operations April 22, 2014

HIV

Antiviral Product Sales Q1 2014 up 119% from Q1 2013 Key Metrics U.S.: (in Millions) $5,000 $4,500 $4,000 $3,500 $3,000 $2,500 $2,000 $1,500 $1,000 $500 $0 $2,061 $750 $2,640 $2,312 $2,327 $756 $750 $795 $3,361 $1,157 $1,373 $1,390 $1,638 $4,508 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 $949 Growth driven by launch of Sovaldi Inventory reduction for HIV and cardiopulmonary products to low-end of normal ranges Europe: Growth driven by launch of Sovaldi and continued uptake of Eviplera Stribild launched in Big-5 as well as fourteen additional countries U.S. Europe Other International 19

U.S. HIV Market Dynamics 1,400 (Estimated Patients in 000's) 1,200 1,000 800 600 400 200 ~1,145* ~84% ~964* ~72% ~693** Up 6%^ ~85% ~587** 0 HIV Infected Diagnosed On Antiretroviral Treatment On a Gilead HIV Product Sources: * CDC estimates at the end of 2010 taken from the HIV Surveillance Supplemental Report vol. 18 no. 5. ** Ipsos Healthcare U.S. HIV Monitor Q4 2013. ^ Growth rate calculated as MAT (moving annual total). 20

Gilead U.S. STR Share in Naïve Patients 100% 90% 90% 80% (% of Naïve Patients) 70% 60% 50% 40% 30% 20% 69% 30% 18% 21% 21% 10% 0% On a Gilead HIV Product Gilead STR Stribild Complera Atripla Truvada Q4 2011 Q4 2012 Q4 2013 Base: All initiations within each quarter. Source: Ipsos Healthcare HIV U.S. Scope & Monitor Q4 2013. 21

Top Prescribed HIV Regimens U.S. Rank Naïve All Patients Europe Big-5 Rank Naïve All Patients 1 Stribild Atripla 1 Eviplera Atripla 2 Atripla Complera 2 Atripla Truvada + other 3 rd Agent 3 Complera Stribild 3 Truvada + other 3 rd Agent Eviplera 4 Truvada + other 3 rd Agent Truvada + other 3 rd Agent 4 Truvada + other 3 rd Agent Truvada + other 3 rd Agent 5 Truvada + other 3 rd Agent Truvada + other 3 rd Agent 5 Stribild Truvada + other 3 rd Agent Source: Ipsos Healthcare HIV U.S. Therapy Monitor Q4 2013. EU Naïve Source: Ipsos Scope Q4 2013. EU All Patient Source: Ipsos (EU) HIV Monitor Q3 2013. Single tablet regimens 22

Stribild Product Sales $250 $225 $200 Q1 2014 up 134% from Q1 2013 $215 $204 U.S.: Key Metrics* Captured 30% of naïve HIV patient share (In Millions) $175 $150 $125 $100 $75 $50 $25 $0 $144 $99 $92 $92 $97 $135 $186 $187 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Third most prescribed HIV regimen across all treated patients Europe: Launched in Big-5 as well as fourteen additional countries *Sources: U.S. data from Ipsos Healthcare HIV U.S. Therapy Monitor Q4 2013. Note: Stribild is indicated for the treatment of HIV-1 infection in antiretroviral treatment-naïve patients. U.S. Europe Other International 23

Complera/Eviplera Product Sales Q1 2014 up 69% from Q1 2013 Key Metrics* $300 $250 $262 $251 U.S.: Captured 18% of naïve HIV patient share (In Millions) $200 $150 $148 $39 $189 $59 $211 $74 $95 $109 Number two most prescribed HIV regimen across all patients Europe: Captured 20% of naïve HIV patient share in Big-5 $100 $50 $103 $120 $127 $153 $130 Preferred status in Big-5 Most switched to HIV regimen in Big-5 $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 U.S. Europe Other International *Sources: U.S. data from Ipsos Healthcare HIV U.S. Therapy Monitor Q4 2013. EU data from Ipsos Healthcare HIV EU Scope Q4 2013. 24

U.S. Stribild and Complera Source of Patients (18 months post-launch) Switch Integrase Inhibitor, 8% Stribild (Aug 2012 Feb 2014) Complera (Aug 2011 Feb 2013) Switch Integrase Inhibitor, 4% Switch PI, 23% Naïve, 40% Switch PI, 19% Naïve, 39% Switch Other, 9% Switch Complera, 5% Switch Atripla, 15% Switch Other, 13% Switch Atripla, 25% Source: IMS Monthly LRx Data (Aug 2011 to Feb 2014), data is subject to restatement. Note: Stribild and Complera are indicated for the treatment of HIV-1 infection in antiretroviral treatment naïve patients. Stribild and Complera are not indicated for use in treatment-experienced patients and are not promoted to such patients. 25

Atripla Product Sales (In Millions) $1,000 $750 $500 $250 $877 $278 $554 Q1 2014 down 11% from Q1 2013 $938 $934 $900 $780 $271 $257 $256 $611 $576 $615 $490 $237 U.S.: Key Metrics* Most prescribed HIV regimen with 28% of all treated patients Captured 21% of naïve HIV patient share Europe: Most prescribed HIV regimen with 22% of all treated patients Captured 19% of naïve HIV patient share** $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 U.S. Europe Other International Note: Efavirenz (the active pharmaceutical component in Atripla purchased from Bristol-Myers Squibb) accounted for approximately 36% of Atripla sales in Q1 2014 which represented $282 million to be paid to BMS. *Sources: U.S. data from Ipsos Healthcare HIV U.S. Therapy Monitor Q4 2013. EU data from Ipsos Healthcare HIV EU Therapy Monitor Q3 2013 & Ipsos Healthcare HIV EU Scope Q4 2013. **Note: In the EU Atripla does NOT have an indication for the treatment of naïve patients and there is NO Atripla promotion concerning treatment naïve patients. 26

Truvada Product Sales (In Millions) $1,000 $750 $500 $250 $0 Q1 2014 up 8% from Q1 2013 $808 $814 $814 $760 $700 $332 $325 $314 $325 $323 $308 $416 $430 $417 $368 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 U.S.: Key Metrics* Captured 32% of all treated HIV patients Captured 21% of naïve HIV patient share Europe: Most prescribed HIV product with 36% of all treated patients Captured 35% of naïve HIV patient share *Sources: U.S. data from Ipsos Healthcare HIV U.S. Therapy Monitor Q4 2013. EU data from Ipsos Healthcare HIV EU Therapy Monitor Q3 2013 & Ipsos Healthcare HIV EU Scope Q4 2013. U.S. Europe Other International 27

HCV

Sovaldi: A New Treatment for Patients Infected with HCV U.S. ~30,000 patients initiated treatment since launch Q1 2014 sales of $2.1 billion o ~70% of usage in GT 1 o Predominately with PegIFN + RBV European Commission approval January 17, 2014 Q1 2014 sales of $164 million o Sales predominately for Germany and France Recently updated EASL guidelines, Sovaldi included in recommendations across all genotypes Pricing and reimbursement discussions throughout the year 29

Wholesale Acquisition Cost* (WAC) per Patient and Corresponding Treatment Duration for HCV Genotype 1 Regimens *Excludes Costs for Adverse Event Management Regimen Cost ($) Duration of Therapy (weeks) OLYSIO TM + PEGASYS + ribavirin 106,673 48 $86,516 INCIVEK + PEGASYS + ribavirin $86,312 VICTRELIS + PEGINTRON + ribavirin $64,825 SOVALDI + PEGASYS + ribavirin $85,257 OLYSIO + PEGASYS + ribavirin $95,845 INCIVEK + PEGASYS + ribavirin $106,673 VICTRELIS + PEGINTRON + ribavirin $106,468 106,468 95,845 94,078 86,516 86,312 85,257 48 48 12 24 24 36 VICTRELIS + PEGINTRON + ribavirin 64,825 28 Therapy duration based on approved dosing for complete course of therapy. Follows full prescribing information recommendations for each product. Total regimen costs assume average weight of typical patient (86.2 kg) calculated using anthropometric reference data for US adults compiled by the US Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) in 2007-2010 and CDC data showing 87% of US individuals were born between 1945 and 1970 and two-thirds of this cohort are male.10,11 Ribavirin costs were based on the average generic price for capsules and tablets. Assumes no dose reduction due to adverse events and that patient takes entire regimen as indicated. Not all components may be used for the full duration. Cost for Pegasys based on the cost of ProClick autoinjectors and prefilled syringes, which are priced the same. Cost for Peg Intron based on the cost of REDIPEN s and single-dose kits (powder + dilutent vials), which are priced the same. For reference only. Cost comparisons of agents do not imply comparable clinical effectiveness, safety, tolerability, or that these products have the same or similar indications or uses. Please refer to the full prescribing information for each product. Individual prescribing decisions should be made at the discretion of the provider. The information reflects WAC prices as reported by First Databank (FDB) on February 27, 2014. Manufacturers change the WAC prices of their products periodically. Current WAC prices may be obtained by contacting FDB. WAC = wholesaler acquisition cost, or manufacturer s published price to wholesalers; WAC represents published catalogue or list prices and may not represent actual transactional prices. For further information concerning pricing methodology, please refer to this section of the FDB website (http://www.fdbhealth.com/policies/drug-pricing-policy/). Pricing information reprinted with permission by First Databank, Inc. All rights reserved. 2014 30

U.S. HCV Market Dynamics (Estimated Patients in 000's) 4,500 4,000 3,500 3,000 2,500 2,000 1,500 1,000 500 0 4.1M ~41% 1.7M ~23% 388 ~10% Prevalence Diagnosed Under Treater Care Treated 40 Sources: Chak et al 2008, Armstrong et al 2005, Volk et al 2011, Culver et al 2000, Decision resources: 2008, CDA AASLD 2012, NHANES 2012, Ipsos Monitor Q4 2013 and Gilead estimates. Note: Data is applicable to the 12 month period beginning January 2013 through December 2013. 31

Europe Big-5 HCV Market Dynamics 3,000 2.8M 2,500 (Estimated Patients in 000s) 2,000 1,500 1,000 ~29% 0.8M 500 0 ~34% 272 ~18% Prevalence Diagnosed Under Treater Care Treated 49 Source: Ipsos Healthcare EU5 HCV Monitor Q4 2012 Q2 2013, IMS/GERS data and Gilead estimates. Note: Data is applicable to the 12 month period beginning January 2013 through December 2013. 32

Japan HCV Market Dynamics (Estimated Patients in 000's) 1,200 1,000 800 600 400 200 0 1.1M ~68% 745 ~5% Prevalence Diagnosed Treated 37 Source: Ipsos HCV Monitor Q212 and Gilead estimates. 33

EASL Guideline Update (April 2014) Sofosbuvir included in recommendations across all HCV genotypes Sofosbuvir included in recommendations for difficult to treat groups: Non-sustained virological responders Compensated cirrhosis Patients with an indication for liver transplantation Post-liver transplantation recurrence Patients with co-morbidities 34

STR of LDV/SOF Regulatory Filings Filed NDA in the U.S. on February 10, 2014 Priority review granted with PDUFA date of October 10, 2014 Granted Breakthrough Therapy designation by FDA Treatment-naïve and treatment-experienced GT 1 patients +/- RBV dosed for 8 or 12 weeks of therapy MAA fully validated by European Medicines Agency (EMA) on March 27, 2014 Granted accelerated review by EMA Agreement with the Japanese Regulatory Agency PMDA: Phase 3 in GT 1 HCV infected patients +/- RBV dosed for 12-weeks fully enrolled December 2013 Anticipate filing for approval in Q4 2014 35

Robin Washington EVP and Chief Financial Officer April 22, 2014

Non-GAAP Diluted EPS Q1 2014 up 207% over Q1 2013 $1.50 $1.48 $1.00 $0.50 $0.48 $0.50 $0.52 $0.55 $0.00 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Note: Non-GAAP diluted EPS excludes acquisition-related, restructuring and stock-based compensation expenses. 37

Total Revenues Q1 2014 up 97% over Q1 2013 $5,500 $5,000 $4,999 $4,500 $4,000 (In Millions) $3,500 $3,000 $2,500 $2,000 $2,532 $2,767 $2,783 $3,120 $1,500 $1,000 $500 $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 38

Non-GAAP Product Gross Margins Key Metrics 100% 75% 74.5% 75.1% 75.7% 74.5% 87.4% Higher Non-GAAP Product Gross Margins Q1 2014 over Q1 2013 driven primarily by Sovaldi sales and favorable HIV mix 50% 25% 0% Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Note: Non-GAAP product gross margins exclude acquisitionrelated and stock-based compensation expenses. 39

Non-GAAP R&D Expenses Q1 2014 up 21% from Q1 2013 Key Metrics $600 $500 $400 $460 $488 $489 $511 $558 Higher R&D expenses in Q1 2014 over Q1 2013 driven primarily by: - Progression of clinical studies in Oncology and HIV (In Millions) $300 $200 $100 $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Note: Non-GAAP R&D expenses exclude acquisition-related, restructuring and stock-based compensation expenses. 40

Non-GAAP SG&A Expenses $600 Q1 2014 up 50% from Q1 2013 Key Metrics Higher SG&A expenses in Q1 2014 over Q1 2013 driven primarily by: (In Millions) $500 $400 $300 $200 $100 $333 $376 $377 $471 $500 - Support the expansion of the business, particularly in HCV and anticipated launch of idelalisib Pharmaceutical excise tax for 2014 is estimated between $150 - $170 million $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Note: Non-GAAP SG&A expenses exclude acquisition-related, restructuring and stock-based compensation expenses. 41

Operating Cash Flows $1,750 $1,500 Q1 2014 up 133% from Q1 2013 $1,568 Key Metrics Higher Operating Cash Flow in Q1 2014 driven by launch of Sovaldi $1,250 (In Millions) $1,000 $750 $672 $953 $753 $727 $500 $250 $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 42

Outstanding Debt (in billions) Dec. 31, 2013 Mar. 31, 2014 2 Senior Credit Facilities $0.60 $0.00 Senior Unsecured Notes $4.70 $8.70 Convertible Notes $1.41 $1.17 Total Debt 1 $6.71 $9.87 1 - Debt amount shown at face value. 2 - $4.0 billion senior unsecured notes issued in March 2014. Total interest expense and amortization from all existing debt sources expected to be approximately $95 million per quarter in 2014 or $380 million for the full year 2014 (includes approximately $135 million incremental interest expense for the full year 2014 related to the $4.0 billion senior unsecured notes issued in March 2014). 43

2014 Share Repurchase Activity Type of Repurchase Dollar Amount (In Millions) Shares Repurchased Average Purchase Price Q1 2014 Open Market $450.0 5,743,223 $78.35 $5.0 billion share repurchase program authorized January 20, 2011, with $2.9 billion remaining as of March 31, 2014. 44

Full Year 2014 Guidance (in millions, except percentages and per share amounts) The following Guidance excludes the impact of Sovaldi Product Sales Initially provided 2/4/14; Reiterated on 4/22/14 Net Product Sales $ 11,300 $ 11,500 Non-GAAP * Product Gross Margin 75% 77% R&D Expenses $ 2,200 $ 2,300 SG&A Expenses $ 2,100 $ 2,200 Effective Tax Rate 28% 29% Diluted EPS Impact of Acquisition- Related and Stock-Based Compensation Expenses $ 0.63 $ 0.66 Estimated Impact of Sovaldi Product Sales: There is approximately 0.75% - 1% improvement in Non-GAAP Product Gross Margin and reduction of Non-GAAP Effective Tax Rate for every $1B in Sovaldi Product Sales * Non-GAAP product gross margin, expense and effective tax rate exclude the impact of acquisition-related and stock-based compensation expenses where applicable. 45

Full Year 2014 Guidance (in millions, except percentages and per share amounts) Projected product gross margin GAAP to non-gaap reconciliation: GAAP projected product gross margin Acquisition related-expenses Non-GAAP projected product gross margin* Initially provided 2/4/14; Reiterated on 4/22/14 70% - 71% 5% - 6% 75% - 77% Projected research and development expenses GAAP to non-gaap reconciliation: GAAP projected research and development expenses Acquisition related-expenses Stock-based compensation expenses Non-GAAP projected research and development expenses $2,367 - $2,512 (36) - (69) (131) - (142) $2,200 - $2,300 Projected selling, general and administrative expenses GAAP to non-gaap reconciliation: GAAP projected selling, general and administrative expenses Acquisition related-expenses Stock-based compensation expenses Non-GAAP projected selling, general and administrative expenses $2,278 - $2,389 (1) - (1) (176) - (188) $2,100 - $2,200 Projected diluted EPS impact of acquisition-related and stock-based compensation expenses: Acquisition related-expenses Stock-based compensation expenses Projected diluted EPS impact of acquisition-related and stock-based compensation expenses $0.49 - $0.51 0.14-0.15 $0.63 - $0.66 * Stock-based compensation expenses have a less than one percent impact on non-gaap projected product gross margin. 46

Commercial Appendix Slides April 22, 2014

U.S. Sovaldi Recommended Dosage and Administration HCV Mono-infected and HCV/HIV-1 Co-infected Adults Treatment Duration Genotype 1 or 4 Sovaldi + PegIFN + RBV 12 weeks Genotype 2 Sovaldi + RBV 12 weeks Genotype 3 Sovaldi + RBV 24 weeks Interferon ineligible: Sovaldi in combination with RBV for 24 weeks can be considered for HCV patients with GT1 infection who are interferon ineligible Transplant patients: Should be used in combination with RBV for treatment of HCV in patients with hepatocellular carcinoma awaiting liver transplantation for up to 48 weeks or until liver transplantation, whichever occurs first Sovaldi Full Prescribing Information. Gilead Sciences, Inc. December 2013. 48

EU Sovaldi Recommended Dosage and Administration HCV Mono-infected and HCV/HIV-1 Co-infected Adults Treatment Genotype 1, 4, 5, or 6 Sovaldi + PegIFN + RBV Sovaldi + RBV Only for use in patients ineligible or intolerant to Peg-IFN Duration 12 weeks 24 weeks Genotype 2 Sovaldi + RBV 12 weeks Genotype 3 Sovaldi + PegIFN + RBV Sovaldi + RBV 12 weeks 24 weeks Transplant patients: Should be used in combination with RBV for treatment of HCV in patients with hepatocellular carcinoma awaiting liver transplantation until liver transplantation Sovaldi Full Prescribing Information. Gilead Sciences, Inc. January 2014. 49

Sovaldi Patient Support Path Program 50

Financial Appendix Slides April 22, 2014

Financial Highlights: Q1 2014 (in millions, except per share amounts) Q1 2014 Q1 2013 % Change Product sales $ 4,871 $ 2,394 104% Antiviral products 4,508 2,061 119% Sovaldi 2,274 NA NM Atripla 780 877 (11%) Truvada 760 700 8% Complera/Eviplera 251 148 69% Stribild 215 92 134% Viread 211 210 0% Letairis 123 118 4% Ranexa 112 96 16% AmBisome 92 85 8% Cayston 36 32 11% Royalty, contract and other revenues Total revenues $ 4,999 $ 2,532 97% Non-GAAP costs and expenses* $ 1,669 $ 1,404 19% COGS 611 611 (0%) R&D 558 460 21% SG&A 500 333 50% Non-GAAP net income* $ 2,488 $ 802 210% Non-GAAP diluted EPS* $ 1.48 $ 0.48 207% 128 138 (7%) *Non-GAAP costs and expenses, net income and diluted EPS exclude the impact of acquisition-related, restructuring and stock-based compensation expenses where applicable. Note: Amounts may not sum due to rounding. 52

Total Product Sales Q1 2014 up 104% over Q1 2013 $5,000 $4,871 $4,000 (In Millions) $3,000 $2,000 $2,394 $2,657 $2,710 $3,043 $1,000 $0 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 53

Product Sales by Geography Q1 2014: $4,871 (in millions) U.S.: $3,625 (74% of Total) (159% YoY Growth) Europe: $1,020 (21% of Total) (25% YoY Growth) Other International: $226 (5% of Total) (28% YoY Growth) Note: Amounts may not sum due to rounding. 54

Other Product Sales (in millions) Q1 2013 Q2 2013 Q3 2013 Q4 2013 Q1 2014 % Change from Q1 2013 Sovaldi NA NA NA $139.4 $2,274.3 NM Viread $210.3 $250.2 $231.6 $266.9 $210.6 0% Letairis $118.1 $128.3 $135.1 $138.5 $122.9 4% Ranexa $96.3 $106.6 $115.8 $129.9 $111.6 16% AmBisome $85.3 $75.1 $97.8 $93.6 $92.1 8% Cayston $31.9 $33.9 $34.6 $38.9 $35.5 11% Hepsera* $26.4 $21.5 $20.3 $12.9 $11.7 (56%) * Generic introduction in Q4 2013. 55

European Total Product Sales Increased 24% Year-over-Year Excluding FX $1,050 $900 $818 $818 $824 $871 $1,020 FX impact to European revenues was favorable $13 million QoQ and favorable $2 million YoY FX impact to international revenues (including ROW) was favorable $11 million QoQ and unfavorable $3 million YoY FX impact to pre-tax income was favorable $16 million QoQ and unfavorable $1 million YoY $750 Q1'14 Q1'13 YoY Excl FX (In in Millions) $600 $450 $300 $150 Atripla $237 $278 (15%) (16%) Eviplera $109 $39 180% 179% Stribild $24 $0 NM NM Truvada $323 $332 (3%) (3%) Viread $84 $88 (5%) (4%) Sovaldi $164 $0 NM NM $0 Q1'13 Q2'13 Q3'13 Q4'13 Q1'14 Hepsera $8 $11 (31%) (31%) AmBisome $60 $60 (0%) 1% Other $12 $9 24% 23% Total $1,020 $818 25% 24% 56

Total Royalty, Contract and Other Revenues Q1 2014 down 7% from Q1 2013 $150 $125 $138 $110 $128 (In Millions) $100 $75 $72 $57 $73 $77 $76 $50 $25 $66 $53 $66 $68 $52 $0 $7 $9 Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Tamiflu Other 57

Non-GAAP Operating Margins 75% 50% Q1 2014 up 50% from Q1 2013 44.5% 44.9% 45.2% 43.6% 66.6% Key Metrics Higher Non-GAAP Operating Margins in Q1 2014 over Q1 2013 primarily due to higher gross margin from Sovaldi sales 25% 0% Q1 13 Q2 13 Q3 13 Q4 13 Q1 14 Note: Non-GAAP operating margins exclude acquisition-related, restructuring and stock-based compensation expenses. 58

Non-GAAP Effective Tax Rate* Q1 2013 Q1 2014 Non-GAAP Effective Tax Rate 23.5% 23.2% The Q1 2013 tax rate included the full year 2012 federal research tax credit which was retroactively extended in January 2013. Without the 2012 research credit the Q1 2013 tax rate was 27.5%. *The Non-GAAP Effective Tax Rate excludes the impact of acquisition-related and restructuring expenses. 59

GAAP to Non-GAAP Diluted Earnings Per Share Reconciliation Q1 2014 GAAP Diluted EPS $1.33 Acquisition-Related Expenses $0.12 Stock-Based Compensation Expenses $0.04 Non-GAAP Diluted EPS $1.48 Note: Amounts may not sum due to rounding. 60

Dilution from Outstanding Convertible Notes 2014 Notes 2016 Notes Total Dilution (3) Average share price Q1 2014 $78.43 Convertible Notes (1) (Outstanding as of March 31, 2014) $209M $959M Conversion Price $22.54 $22.71 Q1 2014 Share Dilution 7.0M 31.9M 39.0M Warrants Warrant Exercise Price $28.38 $30.05 Q1 2014 Share Dilution 35.4M 34.0M 69.3M Total Q1 2014 Dilution from Convertible Notes and Warrants (2) 108.3 M (1) At issuance, the amount outstanding on the 2014 and 2016 convertible notes was $1.25B each. (2) Represents 6% of diluted non-gaap shares outstanding. (3) May not sum/recalculate due to rounding. 61

Other Selected Financial Information (in millions, except days sales outstanding) Dec. 31, 2013 Mar. 31, 2014 Cash, Cash Equivalents & Marketable Securities * $2,570.6 $6,859.0 Interest Expense and Other Income (Expense), net ($84.3) ($94.2) Inventories $2,055.8 $2,140.2 Days Sales Outstanding (Accounts Receivable) 52 51 Common Shares Repurchased During the Quarter $400.0 $450.0 Diluted Shares Used in Per Share Calculation for the Quarter (Non-GAAP) Diluted Shares Used in Per Share Calculation for the Quarter (GAAP) 1,693.2 1,679.0 1,694.2 1,679.9 Common Shares Outstanding 1,534.4 1,537.6 * Increase primarily due to the issuance of senior unsecured notes in March 2014 for a total aggregate principal amount of $4.0 billion. 62

Q1 2014 Earnings Results Conference Call and Webcast April 22, 2014