Specialized investment fund
A specialized investment fund (SIF) is a lightly regulated and tax-efficient regulatory regime in Luxembourg aimed at a broader range of eligible investors. This type of investment fund is governed by the Luxembourg law of 13 February 2007 replacing the law of 1991 defining the legal framework for institutional funds and enlarging the distribution scope to "well-informed investors".
Source: Wikipedia — Specialized investment fund (CC BY-SA 4.0)