Today’s systems on chip (SoCs) require a complex design and verification process. In early design stages, high-level debugging of the SoC functionality is feasible on TLM (Transaction-Level Modeling) descriptions. To ease debugging of such SoC’s models, Assertion-Based Verification (ABV) enables the runtime verification of temporal properties. In the last design stages, RTL (Register Transfer Level) descriptions of hardware blocks expose microarchitectural details. To gain confidence in the validity of system level properties after this TLM-to-RTL synthesis, transaction level assertions must be reverifiable on RTL models. To address that issue, we propose refinement rules for the automatic system level to signal level transformation of PSL assertions (Property Specification Language, IEEE standard 1850). We sketch the architecture of a prototype tool that automates this refinement, and we give some illustrative examples for a realistic use case.