Effective January 1, 2024, the maximum amounts of compensation subject to Railroad Retirement Tier I and Tier II taxes will increase to the following: Tier I maximum will increase to $168,600 from $162,200 and Tier II maximum will increase to $125,100 from $118,800. The Tier I tax consists of two components, a Social Security equivalent (Tier I [SS] 6.20%) component and a Medicare (Tier I [Med] 1.45%) component. The maximum compensation subject to Tier I [SS] tax for 2024 is $168,600. There is no maximum for the compensation subject to Tier I [Med]. The Tier II rate for employees will remain at 4.9% for 2024. The maximum compensation subject to Tier II tax for 2024 is $125,100