Description: This article discusses important implications of the upcoming Long-Duration Targeted Improvements (LDTI) accounting change for the modeling actuary. We discuss the modeling implications of new GAAP standards for Market Risk Benefit (MRB), including identification of MRBs, implementation of fair valuation in actuarial systems and retroactive determination of at-issue valuation inputs for transition. We also examine the modeling implications of the other aspects of the accounting change, including Liability for Future Policy Benefit (LFPB), Deferred Acquisition Cost (DAC), and other transition and disclosure requirements