Based on Belgian income tax law, if no or insufficient prepayments are made or wage taxes are withheld at source, a tax increase will be imposed upon assessment of self-employed taxpayers and remunerated company directors.
The new base rate for calculating this increase was published in the Royal Decree of 21 February 2014. As of tax year 2015 (income year 2014) the base rate will be 0.75% (this was 1% in tax year 2013 and 2014). As a result the tax increase that applies to insufficient tax prepayments or withholdings amounts to 1.69%.
Note that the date for making voluntary pre-payments for the first quarter is set at 10 April 2014 at the latest.