Key legal question
Whether personal AHV contributions of a self-employed person are deductible in tax year 2005 despite relating to earlier business years.
Extracted holding
Personal AHV contributions are in principle deductible, but they must be accrued in the relevant year; later deduction is allowed only for minor allocation errors.
Extracted reasoning
The court applied the periodicity principle. Because the taxpayer kept books and had already booked and then prematurely dissolved an AHV provision, the 2001 contribution could not be deducted in 2005. The 2003 contribution was small enough to fall within the court's tolerance for minor allocation errors.