® Proteins by Design® XmAb® Antibody Therapeutics Corporate Overview January 2025

2 Forward-Looking Statements Certain statements contained in this presentation, other than statements of historical fact, may constitute forward- looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Such statements include, but are not limited to, statements regarding Xencor's development plans and timelines; potential regulatory actions; expected use of cash resources; the timing and results of clinical trials; the plans and objectives of management for future operations; and the potential markets for Xencor's product and development candidates. Forward-looking statements are based on the current expectations of management and upon what management believes to be reasonable assumptions based on information currently available to it, and involve numerous risks and uncertainties, many of which are beyond Xencor's control. These risks and uncertainties could cause future results, performance or achievements to differ significantly from the results, performance or achievements expressed or implied by such forward-looking statements. Such risks include, but are not limited to, potential delays in development timelines or negative preclinical or clinical trial results, reliance on third parties for development efforts and changes in the competitive landscape including changes in the standard of care, as well as other risks described in Xencor's filings with the Securities and Exchange Commission (SEC). Xencor expressly disclaims any duty, obligation or undertaking to update or revise any forward-looking statements contained herein to reflect any change in Xencor's expectations with regard thereto of any subsequent change in events, conditions or circumstances on which any such statements are based, except in accordance with applicable securities laws. For all forward-looking statements, we claim the protection of the safe harbor for forward looking statements contained in the Private Securities Litigation Reform Act of 1995.

3 • XmAb Fc Domains augment native immune functions in molecules and/or control their structure, while preserving desired attributes • XmAb engineered antibodies are designed to solve complex biologic problems • Strong patent portfolio with over 1,600 patents issued and pending worldwide • Oncology: 3 novel TCEs advancing in Phase 1 studies; narrow focus for vudalimab in mCRPC and 1L NSCLC • Autoimmune: Study initiations and plans • 4Q’24: XmAb942 (Xtend TL1A) • 1H’25: Plamotamab (CD20xCD3) in RA • 2H’25: XmAb657 (CD19xCD3) • More than 15 technology license partnerships greatly broadens scope with little-to-no effort • Multiple commercialized XmAb antibodies ULTOMIRIS® MONJUVI®/MINJUVI® Proven Power of XmAb® Engineering: Proteins By Design® AstraZeneca Rare Disease Small changes, big functional impacts Advancing an optimized portfolio of XmAb drug candidates Partnerships leverage modular XmAb technology Registered trademarks: Ultomiris® (Alexion Pharmaceuticals, Inc.), Monjuvi® & Minjuvi® (Incyte Holdings Corp.) COLLABORATION PORTFOLIO INCLUDES XmAb Bispecific T-cell Engagers (TCEs) Xtend Antibodies with Potential Best-in-class Half-life Extension PLUG & PLAY TOOLKITS FOR RAPID PROTOTYPING RATIONALLY ENGINEERED XMAB DRUG CANDIDATES 

4 World-leading protein engineers and proven XmAb® Fc platforms, supported by strong financial position of approximately $707 million* Experienced drug development team deliver rapid proof-of-concept clinical studies Rapidly prototype and optimize XmAb® drug candidates, designed with purpose to solve complex biological engineering problems Long-term potential benefit for patients through strict evaluation of data and competition to drive internal advancement towards commercialization or collaboration Xencor’s Disciplined Drug Development Strategy Validated Best-in-Class XmAb® Platforms Optimally Engineered Novel Drug Candidates Maximize Outcomes for All Stakeholders Focused Clinical Execution XmAb® Drug Development Model * Unaudited. As of 12/31/2024. Includes cash, cash equivalents & marketable debt. Updated 13-Jan-2025.

5 Program Targets XmAb® Platforms Indications Discovery Preclinical Phase 1 Phase 2 Phase 3 Solid Tumor Oncology: T-cell Engagers (CD3 & CD28) XmAb819 ENPP3 x CD3 2+1 Bispecific ccRCC XmAb808 B7-H3 x CD28 2+1 Bispecific, Xtend Prostate cancer, oncology XmAb541 CLDN6 x CD3 2+1 Bispecific, Xtend Ovarian cancer, oncology XmAb Program Undisclosed TCE Bispecific, Xtend Solid tumor oncology Solid Tumor Oncology: T-cell Selective, Dual Checkpoint Inhibitor Vudalimab PD-1 x CTLA-4 Bispecific, Xtend mCRPC 1L NSCLC Immunology Programs Plamotamab CD20 x CD3 Bispecific Rheumatoid Arthritis XmAb942 TL1A Xtend, FcKO Inflammatory Bowel Diseases (IBD) XmAb657 CD19 x CD3 2+1 Bispecific, Xtend Autoimmune Diseases XmAb Program TL1A x IL23 Bispecific, Xtend Autoimmune Diseases + chemotherapy Solid tumors Immunology + pembrolizumab +/- chemotherapy Key ccRCC clear cell renal cell carcinoma NSCLC non-small cell lung cancer mCRPC metastatic castration-resistant prostate cancer FcKO Fc knock out 1H’25 2H’25 Planned Study Initiation Next-Gen XmAb® Drug Design in Oncology & Autoimmune Diseases Pipeline focus on T-cell engagers and bispecific mechanisms

6 XmAb® Technologies Create Numerous Differentiated Antibodies for Technology Partners Selected Programs Fc Domain Indications Preclinical Phase 1 Phase 2 Phase 3 Marketed Commercial Rights Ultomiris® Xtend PNH, aHUS, gMG, NMOSD Monjuvi® Cytotoxic DLBCL Obexelimab Immune Inhibitor IgG4-RD, wAIHA Tobevibart (VIR-3434) Cytotoxic Xtend Hepatitis B Hepatitis D Xaluritamig STEAP1 x CD3 2+1 Bispecific Prostate cancer Efbalropendekin alfa IL15/IL15Rα-Fc Bispecific Xtend r/r multiple myeloma ASP2138 CLDN18.2 x CD3 2+1 Bispecific Oncology JNJ-9401 PSMA x CD28 Bispecific Prostate cancer JNJ-1493 CD20 x CD28 Bispecific Heme-Onc Technology licensing expands pipeline with very little opportunity cost AstraZeneca Rare Disease + cevostamab XmAb BispecificKey XmAb Tech (Non-BsAb)Xevudy® (sotrovimab), with Xencor’s Xtend Fc Domain, was provided under emergency use authorization for COVID-19, but is not currently authorized in the U.S. Registered trademarks: Ultomiris® (Alexion Pharmaceuticals, Inc.), Monjuvi® (Incyte Holdings Corp.), Xevudy® (Glaxo Group Limited)

7 ® XmAb® Bispecific T Cell Engagers XmAb 2+1 Bispecific Antibody Format XmAb819 (ENPP3 x CD3) XmAb541 (CLDN6 x CD3) XmAb808 (B7-H3 x CD28)