Tesis (magister en derecho internacional) / The recent globalized economy, and the substantial number of bilateral and multilateral agreements that have been signed, have become a constant incentive to foreign investors willing to invest in a host State. For its part, the host State is also concerned with investments, specifically with the restraint on its regulatory powers when it is in compliance with its treaties. Many countries today receive a great amount of foreign direct investment (FDI). It is this substantial level of FDI that is part of the source of the rapid development of countries we see these days. The idea of State expropriation is an act which is recognized in the international plane, which it is established pursuant the public interest and its requirements. The problem arises when the act does not regard a direct taking which is “more noticeable”, but appears certain conducts of the State disguised as “measure pursuant the public interest”, when actually is trying to control or deprive the investor form its peaceful enjoyment of its assets without the proper compensation. I will deal with the different concepts of expropriation, indirect expropriation in its different forms, such as regulatory takings, creeping expropriation, and measures tantamount to expropriation in order to establish how government’s measures take place and harm private owners. I will analyze the current treaties on investment, the principles that can be extracted in today’s BIT and Regional Agreements such as NAFTA, and the main problem of the lack of a concrete definition of expropriation, which today is saved by the principles of international customary law. Then I will analyze the denominator problem, which deals with the dilemma Courts face when determining the extent of damage to the property owner’s assets, which may regard a compensable act of expropriation, the way courts try to define the relevant parcel affected by the government’s measure, and if that harm amounts a damage to the investment, great enough to be compensable, or simply regards a burden, the investor must bear, in order for the State to fulfill the public interest. Finally I will analyze the recent jurisprudence regarding foreign investor claims against outright deprivations by the host State, and the evolution of the diverse concepts and principles extracted of those awards. To summarize I will establish when the State has the legitimacy to affect foreign private property, under what circumstances can do so, when privates have been affected in their property, in a way that entitles them to compensation for the harm caused by the State, when can we talk about expropriation or indirect expropriation of investment (affectation of property at its core and to its periphery), and finally what are the principles that can be extracted through the different treaties signed, the diverse concepts regarding indirect expropriation and of the recent jurisprudence on these muddied matters judges are somewhat reluctant to address in the international plane.

La nulidad de oficio en sede administrativa es una de las potestades de autotutela que detenta la administración pública para corregir sus decisiones cuando se configuren algunas de las causales de nulidad señaladas en el artículo 10 del Texto Único Ordenado de la Ley del Procedimiento Administrativo General, Ley N° 27444, aprobado mediante Decreto Supremo N° 004-2019-JUS (en adelante, TUOLPAG); y, cuando se produzca una afectación al interés público, según la norma señalada. Es así que a través de la Resolución N° 057-2016-CD/OSIPTEL (en adelante, la Resolución), el Consejo Directivo del Organismo Supervisor de Inversión Privada en Telecomunicaciones (en adelante CD y OSIPTEL, respectivamente) anuló de oficio la multa ascendente a 2 Unidades Impositivas Tributarias (UIT) en un primer momento impuesta a TELEFÓNICA DEL PERÚ S.A.A. (en adelante, TELEFÓNICA), en el marco de un procedimiento administrativo sancionador, modificándola a una de 51 UIT. En el presente trabajo, se expondrá si la decisión tomada por el máximo órgano del OSIPTEL fue correcta, a partir de su propia jurisprudencia administrativa, así como la normativa pertinente, tal como la Ley N° 27336, Ley de Desarrollo de Funciones y Facultades del OSIPTEL (en adelante, la LDFFO), el Reglamento General de Infracciones y Sanciones, aprobado mediante Resolución N° 087-2013-CD/OSIPTEL y modificatorias (en adelante, el REGIS), y el Texto Único Ordenado de las Condiciones de Uso, aprobado mediante Resolución de Consejo Directivo Nº 138-2012-CD/OSIPTEL y sus modificatorias (en adelante TUOCDU). En base a un análisis del contenido de la Resolución materia del presente informe, se sostendrá que dicha decisión no sería jurídicamente válida al haberse vulnerado: (i) el debido procedimiento administrativo; (ii) configurarse la retroactividad benigna; y, (iii) por la inexistencia de algún tipo de agravio al interés público por la primera multa impuesta, por lo que se debió aplicar lo señalado en la LDFFO y no lo establecido en el REGIS del OSIPTEL. / The ex officio annulment at administrative headquarters is one of the self-protection powers held by the public administration to correct its decisions when some of the causes of annulment indicated in article 10 of the Single Ordered Text of the Law of General Administrative Procedure, Law are configured. No. 27444, approved by Supreme Decree No. 004-2019-JUS (hereinafter, TUOLPAG); and, when there is an impact on the public interest, according to the indicated standard. Thus, through Resolution No. 057-2016- CD/OSIPTEL (hereinafter, the Resolution), the Board of Directors of the Supervisory Body for Private Investment in Telecommunications (hereinafter CD and OSIPTEL, respectively) annulled the fine ex officio amounting to 2 Tax Units (UIT) initially imposed on TELEFÓNICA DEL PERÚ S.A.A. (hereinafter, TELEFÓNICA), within the framework of an administrative sanctioning procedure, modifying it to one of 51 UIT. 3 In this work, it will be explained whether the decision made by the highest body of OSIPTEL was correct, based on its own administrative jurisprudence, as well as the relevant regulations, such as Law No. 27336, Law on the Development of Functions and Powers of the OSIPTEL (hereinafter, the LDFFO), the General Regulation of Infractions and Sanctions, approved by Resolution No. 087-2013-CD/OSIPTEL and amendments (hereinafter, the REGIS), and the Single Ordered Text of the Conditions of Use, approved by Resolution of the Board of Directors No. 138-2012-CD/OSIPTEL and its amendments (hereinafter TUOCDU). Based on an analysis of the content of the Resolution that is the subject of this report, it will be argued that said decision would not be legally valid since: (i) due administrative procedure was violated; (ii) benign retroactivity is configured; and, (iii) due to the absence of any type of offense to the public interest due to the first fine imposed, so what was stated in the LDFFO should have been applied and not what was established in the OSIPTEL REGIS.