As of January 1, 2018, the legislator has fundamentally restructured investment tax law with the Investment Tax Reform Act. For investment funds, the previous principle of transparency has been abandoned in favor of an opaque taxation system based on the separate taxation of funds and investors. However, there are also fundamental changes in the area of special investment funds, where the current semi-transparent taxation procedure will continue, with the stipulation that not all income is attributed to the investor. The taxation regime for investment companies introduced by the AIFM-StAnpG will be integrated into these systems. The new law raises numerous questions of doubt for management companies, custodians, and investors. This second volume of the Frankfurt Commentary on Capital Investment Law serves as a comprehensive commentary on the subject.