Additional Tier 1 capital. AT1 is one of the two components of Tier 1 capital, the highest quality capital under the Basel framework, with the other being common equity Tier 1 (or CET1). In order for an instrument to constitute AT1, it must meet the prescriptive criteria identified in the final Basel III framework, such as an ability to absorb losses, subordination, fully discretionary non-cumulative dividend payments, no incentive to repay or redeem, etc. AT1 also may be referred to as “non-core” Tier 1. AT1 is subordinate to depositors, general creditors, and subordinated debt of the bank.