As the influence of Sovereign Wealth Funds (SWFs) is increasing in the world economy, the legal problems between the possessing States and recipient States become very important. The famous Santiago Principles are self-pledges of the governance and activities of SWFs by the possessing States and do not regulate the legal problems between the possessing States and the recipient States. This article considers the following relevant problems from the point of international law: (A) restrictions on foreign investment, (B) sovereign immunity, (C) taxation and (D) responsible investment. As to (A), although restrictions on foreign investment for national security reasons is generally permitted under international law, they should be guided by the principles of non-discrimination, transparency of policies and predictability of outcomes, proportionality of measures and accountability of implementing authorities. As to (B), when SWFs are involved in a civil action concerning holding shares in a company, they canno...