The key divergence is conceptual: US GAAP takes an integral view, IFRS a discrete view — which changes how some costs hit interim periods.
| Area | US GAAP (ASC 270) | IFRS (IAS 34) |
|---|---|---|
| View | Integral — an interim period is part of the annual period | Discrete — each interim period stands on its own |
| Cost recognition | Some costs allocated/estimated across the year | Recognized in the interim period incurred (with exceptions) |
| Income taxes | Estimated annual effective rate | Estimated annual effective rate (a discrete-view exception) |
The integral vs discrete distinction affects interim inventory write-downs, certain accruals, and cost deferrals.
An educational reference and original synthesis — not investment advice, and not a substitute for the standard. Consult ASC 270 / IAS 34 directly.