Typical financial modelling mistakes include
- Forgetting to copy formulae right-across all columns
- Inserting a constant (hard-plug) in a calculation sheet (for „comfort“ reasons) and forgetting to replace it with a link / formula
- Sums are wrongly built (esp. after inserting rows at the top or at the bottom of the area to be summed up)
- Over-anchoring of constants ($I$4 instead of $I4)
- Unwanted circularities
Further, errors that a financial model reader will easily spot include
- Price-/quantity grid not given or not documented
- Financing gaps or too much credit is drawn
- Seasonality effects not covered
- Tax issues: Bridge financing of VAT missing, loss-carry-forward of income tax not properly modeled
- Financial covenants broken
- Certain parts are modeled in extreme detail, other parts only rudimentary