Historical cost (trended)
We add up what was actually spent on research, development, filing, prosecution and maintenance, then restate each year's spend in today's money using an inflation index.
Trended cost = Σ Costₜ × (CPI_valuation date ÷ CPIₜ)
- When we use it
- Early-stage IP with no revenue yet; as a floor value or cross-check.
- Key inputs
- R&D and personnel costs by year; Filing and attorney fees; Inflation index
- Watch-outs
- Spending money does not create value by itself — historical cost can overstate failed research or understate a lucky breakthrough.