Employers – Payment of deferred employer share of social security tax from 2020. If the employer deferred paying the employer share of social security tax or the railroad retirement tax equivalent in 2020, 50% of the deferred amount of the employer share of social security tax was due by January 3, 2022. The remaining 50% of the deferred amount of the employer share of social security tax is due by January 3, 2023. Any payments or deposits made before January 3, 2022, were first applied against the payment due by January 3, 2022, and then applied against the payment due on January 3, 2023.