spending for the full year ended December 31, 2021 compared to 2020 reflects increased staffing, facility costs and additional spending on professional services, including intellectual property costs and licensing fees.
Non-cash, share based compensation expense for the year ended December 31, 2021 was $37.0 million, compared to $31.6 million for the year ended December 31, 2020.
Net income for the fourth quarter ended December 31, 2021 was $73.1 million, or $1.21 on a fully diluted per share basis, compared to a net loss of $13.7 million, or $(0.24) on a fully diluted per share basis, for the same period in 2020. For the full year ended December 31, 2021, net income was $82.6 million, or $1.37 on a fully diluted per share basis, compared to a net loss of $69.3 million, or $(1.21) on a fully diluted per share basis, for the full year ended December 31, 2020. Higher net income reported for 2021 compared to 2020 is primarily due to increased royalties and revenue recognized from collaborations in 2021.
The total shares outstanding were 59,355,558 as of December 31, 2021, compared to 57,873,444 as of December 31, 2020.
Financial Guidance
Based on current operating plans, Xencor expects to have cash to fund research and development programs and operations through the end of 2025. Xencor expects to end 2022 with between $500 million and $550 million in cash, cash equivalents, receivables and marketable debt securities.
Conference Call and Webcast
Xencor will host a conference call today at 4:30 p.m. ET (1:30 p.m. PT) to discuss full year 2021 financial results and provide a corporate update.
The live call may be accessed by dialing (877) 359-9508 for domestic callers or +1 (224) 357-2393 for international callers and referencing conference ID number 5290676. A live webcast of the conference call will be available online from the Investors section of the Company's website at www.xencor.com. The webcast will be archived on the company's website for 30 days.
About Xencor, Inc.
Xencor is a clinical-stage biopharmaceutical company developing engineered antibodies and cytokines for the treatment of patients with cancer and autoimmune diseases. More than 20 candidates engineered with Xencor's XmAb® technology are in clinical development, and three XmAb medicines are marketed by partners. Xencor's XmAb engineering technology enables small changes to a protein's structure that result in new mechanisms of therapeutic action. For more information, please visit www.xencor.com.
Forward-Looking Statements
Certain statements contained in this press release may constitute forward-looking statements within the meaning of applicable securities laws. Forward-looking statements include statements that are not purely statements of historical fact, and can generally be identified by the use of words such as “potential,” “can,”