I frequently receive calls from employees who describe to me how they have recently been wronged by their employer and terminated. These stories usually end with the question, "Can they do that?" In essence, they want to know if they are a victim of wrongful termination.
Unless you are protected by a contract or are a union or government employee, in the state of California employees are considered "at-will." "At-will" means that the employment relationship may be terminated by the employee or the employer, at any time, at the will of either party. Typically, unless there is an agreement to the contrary, no notice or warning is required.
My answer then, usually, is, "Yes, they can do that." Employers can fire employees because it's Tuesday, or because business is down, or due to poor performance, or even by mistake. At-will employees can be fired for any reason, except one that violates a recognized public law or public policy. For example , it is unlawful to fire an employee for discriminatory reasons based on race, religion, gender, color, national origin, ancestry, disability, medical condition, marital status, age (over 40), sexual orientation or denial of family medical leave; or in retaliation for reporting the unlawful conduct of an employer.
Employers in California, therefore, have wide discretion in their termination decisions, as long as they are compliant with the law. So if you've recently lost your job and have concerns, seek out the advice of an attorney before taking any action. Every situation is unique and must be evaluated on its own facts and applicable law.