Exhibit 99.1 XOMA Reports Fourth Quarter and Full Year 2023 Financial Results and Highlights Recent and Upcoming Events Expected to Drive Shareholder Value Raised up to $140 million of non-dilutive non-recourse capital through a royalty-backed loan related to VABYSMO® from funds managed by Blue Owl Capital Received $15.5 million in cash payments related to our growing royalty base and the achievement of certain development milestones during 2023 Added third commercial asset to XOMA's portfolio with the acqu ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT For the transition period from __________to__________ Commission File No. 001-39801 XOMA Corporation (Exact name of registrant as specified in its charter) Delaware 52-2154066 (State or other ju ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION For the transition period from __________to__________ Washington, D.C. 20549 Commission File No. 001-39801 FORM 10-Q XOMA Corporation ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT (Exact name of registrant as specified in its charter) For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT If an emerging growth company, indicate by ...

Financial Performance - For the three months ended March 31, 2023, total revenues were $437,000, a decrease of $2.67 million compared to $3.1 million in the same period in 2022[239]. - The company reported a net loss of $9.8 million for the three months ended March 31, 2023, with an accumulated deficit of $1.2 billion as of the same date[233]. - Cash and cash equivalents decreased to $44.3 million as of March 31, 2023, down from $57.8 million at the end of 2022, reflecting a net decrease of $13.5 million[248]. - Net cash used in operating activities for the three months ended March 31, 2023, was $4.9 million, compared to $1.0 million for the same period in 2022[250]. - The company incurred arbitration settlement costs of $4.1 million during the three months ended March 31, 2023[245]. - Net cash used in financing activities for the three months ended March 31, 2023, was $1.4 million, primarily due to dividend payments on Series A and Series B Preferred Stock[252]. Expenses - Research and development (R&D) expenses were $54,000 for the three months ended March 31, 2023, consistent with $56,000 for the same period in 2022[242]. - General and administrative (G&A) expenses increased to $6.2 million for the three months ended March 31, 2023, up from $5.1 million in the same period in 2022, primarily due to increased stock-based compensation and consulting costs[244]. - The company anticipates an increase in operating expenses in 2023 due to a higher volume of acquisition targets being evaluated[259]. Investments and Acquisitions - The company entered into a commercial payment purchase agreement (CPPA) in March 2023, acquiring a mid-single digit percentage payment stream on IXINITY sales, with an upfront payment of $9.6 million[234]. - Net cash used in investing activities was $7.2 million for the three months ended March 31, 2023, primarily due to the $9.6 million payment for the acquisition of payment rights[251]. - The company expects to continue deploying capital toward acquiring rights to potential future milestone and royalty streams in the near and long term[261]. - Potential future milestone payments and legal fees under licensing agreements could aggregate up to $6.3 million, contingent on the achievement of specific milestones[264]. Cash Management - The company had approximately $4.5 million of cash and cash equivalents in accounts with SVB at the time of its closure on March 10, 2023, but regained full access to $3.7 million by March 31, 2023[254]. - Investment income increased to $381,000 for the three months ended March 31, 2023, compared to $15,000 in the same period in 2022, due to higher market interest rates[246]. Preferred Stock and Dividends - Holders of Series A Preferred Stock are entitled to cumulative cash dividends at a rate of 8.625%, while Series B Preferred Stock dividends are at 8.375%[265]. - The company incurred a cost of $4.1 million in April 2023 due to an adverse arbitration decision regarding a license agreement[258]. - The company may seek additional capital through its 2018 Common Stock ATM Agreement or 2021 Series B Preferred Stock ATM Agreement[255]. Lease and Future Outlook - The amended headquarters lease is set to expire in July 2023, with no expected material incremental costs associated with future leases[260].

FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-39801 XOMA CORPORATION (Exact name of registrant as specified in its charter) Delaware 52-2154066 (State or other jurisdiction ...

1 CORPORATE PRESENTATION NOVEMBER 2022 NASDAQ: XOMA A ROYALTY AGGREGATION COMPANY DISCLAIMERS Certain statements in this presentation are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, including statements regarding: future potential monetization opportunities, active transactions with significant financial implications, collaborations poised for significant financial contribution, our library of potentially ...

Company Overview - XOMA has a portfolio of over 70 assets across more than 30 disclosed indications[8] - XOMA focuses on acquiring drug royalties associated with mid- to early-stage clinical candidates, particularly those with blockbuster potential licensed to large-cap partners[8] - XOMA's royalty interests are not diluted as companies raise capital[8] Portfolio Advancements and Key Assets - Since 2017, XOMA's portfolio has seen over 25 advancements from phase to phase[13] - Roche's faricimab, in which XOMA holds a 0.5% royalty, has been approved by the FDA for the treatment of nAMD and DME[16, 49] - Key portfolio assets include NIS793 (Novartis), iscalimab (Novartis), MK-4830 (Merck), osocimab (Bayer), and cetrelimab (Janssen), with royalty rates ranging from low single-digit to low teens percentages[16] Financial and Operational Highlights - XOMA acquired economic interest in Roche's faricimab from Affitech for $6 million upfront[38] - XOMA earned a $35 million milestone from Novartis with the first patient dosed in the NIS793 Phase 3 mPDAC study[38] - XOMA has over $1 billion in potential milestones across its portfolio[52, 60, 63, 66]

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT For the quarterly period ended June 30, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT For the transition period from __________to__________ Commission File No. 001-39801 XOMA Corporation (Exact name of registrant as specified in its charter) Delaware 52-2154066 (State or other jurisdi ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT For the quarterly period ended March 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT (Exact name of registrant as specified in its charter) Delaware 52-2154066 (State or other jurisdiction of (I.R.S. Employer incorporation or organization) Identification No.) 2200 Powell Street, Sui ...

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 or 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 FOR THE TRANSITION PERIOD FROM TO Commission File Number 001-39801 XOMA CORPORATION (Exact name of registrant as specified in its charter) Delaware 52-2154066 (State or other jurisdiction ...