What benefit does the Cohan Rule provide for taxpayers with incomplete business records? The business or taxpayer will be allowed to estimate and deduct certain types of business expenses only if:

The taxpayer provides a reasonable basis for estimating the amount of the expense.

It is clear the expenditure was actually incurred and the taxpayer provides a reasonable basis for estimating the amount of the expense.

It is clear the expenditure was actually incurred.

It is for 100% of business travel and the taxpayer provides a reasonable basis for estimating the amount of the expense.