How does HGB scheduled goodwill amortization work, and what if useful life cannot be reliably estimated?

Under HGB, goodwill is amortized systematically over its useful life. If the useful life cannot be reliably estimated, German rules use a default period. This creates recurring amortization expense and lowers EBIT compared with IFRS. For valuation, add back goodwill amortization when comparing HGB reporters to IFRS reporters, but still consider impairment and economic overpayment risk.