Koos Boer

Koos Boer


Koos Boer has been a professor of tax law at Leiden University since 2013. Koos Boer, together with Allard Lubbers, started what is now Lubbers, Boer & Douma in March 2013.

Previously, he worked in the tax advisory practice of a Big Four firm for more than 12.5 years. Koos received his PhD on the integration of the Anglo-American trust into Dutch personal and corporate tax law from Leiden University in 2011. He specializes in Dutch personal and corporate income tax and also counts payroll tax, transfer tax and gift and inheritance tax among his areas of expertise. Clients he works with range from private equity and real estate investors, to high net worth individuals, Dutch General Benefit Organizations (in Dutch: ANBIs) and (multi)national corporations.

He is also an annotator for the case law journals BNB and NTFR, an editor of Fiscaal Weekblad FED and, among other things, a regular contributor to the Weekblad voor fiscaal recht (WFR) and the Nederlandse Documentatie Fiscaal Recht (NDFR). He was a deputy judge at the District Court (Rechtbank) Noord-Holland (then: Rechtbank Haarlem) for many years and later a deputy judge at the Court of Appeal (Gerechtshof) Arnhem-Leeuwarden. Koos regularly gives lectures and teaches courses. Koos is also a board member of the Tax & Customs Museum (Belasting & Douane Museum) in Rotterdam.

Other positions

  • Professor of tax law
  • Editor Fiscaal Weekblad FED
  • Contributor to the legal journals: WFR, BNB, NTFR and NDFR)
  • Annotator BNB and NTFR
  • Board member Tax & Customs Museum (Belasting & Douane Museum)

Featured publications

  • The APV regime after the death of the contributor and the attribution to (fictitious) heirs, WFR 2023/212 (with X.G.R. Auerbach)
  • Amor fati and box 3: the real estate STAK, WFR 2023/67
  • HR 14 April 2023, no. 20/04413, BNB 2023/122 (10%-criterion lucrative interest)
  • A capital gains tax: not to be 'enjoyed'!, NTFR 2022/3382
  • De internationale aspecten van de voorgestelde Wet excessief lenen bij eigen vennootschap, WFR 2020/175 (with E.J.W. Heithuis)
  • De nationale aspecten van de voorgestelde Wet excessief lenen bij de eigen vennootschap, WFR 2020/170 (with E.J.W. Heithuis)