(b) conditional access systems and other associated software or hardware facilities. (4) (New, SG No. 105/2011, effective 29.12.2011) The parties affected by the amendment or withdrawal of obligations under Paragraph (3) shall be given a sufficient period of notice of the forthcoming amendment or withdrawal of the obligations. Article 156. (1) (Amended, SG No. 105/2011, effective 29.12.2011) In the cases where, on the basis of an analysis of a relevant market, it is ascertained that competition is not effective, the Commission shall identify undertakings which individually or jointly have a significant market power on a relevant market and shall impose specific obligations on any such undertaking or undertakings. (2) (Amended, SG No. 105/2011, effective 29.12.2011) In case specific obligations have been imposed on the undertaking or undertakings with significant market power, the Commission shall maintain the validity of the said obligations or, where appropriate, shall amend the said obligations. (3) (Repealed, SG No. 105/2011, effective 29.12.2011). (4) (Repealed, SG No. 105/2011, effective 29.12.2011). (5) (New, SG No. 105/2011, effective 29.12.2011) The Commission can determine that two or more undertakings jointly have a significant market power if, even in the absence of structural or other links between them, they operate in a market which is characterized by a lack of effective competition and in which no single undertaking has significant market power. (6) (New, SG No. 105/2011, effective 29.12.2011) In case an undertaking has significant market power on a specific market, it may also be designated as an undertaking having significant market power on a closely related relevant market where, on the basis of a market analysis, it is ascertained that the links between the two markets allow the market power held by the undertaking in the first market to be leveraged into the second market, thereby strengthening the market power of the undertaking. (7) (New, SG No. 105/2011, effective 29.12.2011) In the cases referred to in Paragraph (6), the Commission may impose on the undertaking specific obligations according to Items 1, 2, 3 and 5 of Article 166 (2) herein in the second market as well, intended to prevent leverage of the significant market power of the said undertaking to the second market and, where such specific obligations are insufficient, obligations according to Article 221 (3) herein shall be imposed as well. Article 156a. (New, SG No. 105/2011, effective 29.12.2011) In designating a particular undertaking as an undertaking with significant market power on a relevant market, as well as in designating undertakings which jointly have a significant market power on a relevant market, the Commission shall have regard to the criteria established in the methodology referred to in Article 150 (2) herein. Article 157. (Amended, SG No. 105/2011, effective 29.12.2011) Upon determination of the specific obligations which the Commission may impose, maintain, amend or withdraw, the Commission must respect the following principles: 1. proportionality of the obligations imposed considering the reason for the ineffective competition ascertained and the result sought; 2. justification; 3. introduction of regulatory intervention on emerging markets, even where the existence of a market entrant or entrants with large market shares has been ascertained. Article 157a. (New, SG No. 105/2011, effective 29.12.2011) (1) The Commission shall define, analyze and assess relevant markets and shall impose, maintain, amend or withdraw specific obligations on undertakings with significant market power on relevant markets: 1. within three years from determining specific obligations for the undertaking or undertakings with significant market power on the same relevant market; this period may be extended for up to three additional years after the Commission approaches the European Commission with a reasoned proposal for extension, in case the European Commission has not objected to the said proposal within one month after receipt thereof; 2. within two years after amendment of the relevant act of the European Commission defining