Foreign investment in printed media (press) is limited to 49% of equity ownership.
"Section 4
In this Act, “foreigner” means:
1. a natural person who is not of Thai nationality;
2. a juristic person not registered in Thailand;
3. a juristic person registered in Thailand, being of the following descriptions: 
a. being a juristic person at least one half of capital shares of which are held by persons under (1) or (2) or a juristic person in which investment has been placed by the persons under (1) or (2) in the amount at least equivalent to one half of the total capital thereof;
b. being a limited partnership or a registered ordinary partnership the managing partner or the manager of which is the person under (1);
4. a juristic person registered in Thailand at least one half of the capital shares of which are held by persons under (1), (2) or (3) or a juristic person in which investment has been placed by the persons under (1), (2) or (3) in the amount at least equivalent to one half of the total capital thereof; [...]
[...]
Section 8
Subject to section 6, section 7, section 10 and section 12:
1. no foreigner may operate such businesses stricto sensu not permissible to foreigners by special reason, as prescribed in List One;
2. no foreigner may operate such businesses related to national safety or security, businesses having impacts on arts, culture, traditions, customs and folklore handicrafts or businesses having impacts on natural resources or the environment, as prescribed in List Two, unless upon obtaining permission from the Minister with the
approval of the Council of Ministers;
3. no foreigner may operate such businesses in respect of which Thai nationals are not yet ready to compete with foreigners, as prescribed in List Three, unless upon obtaining permission from the Director-General with the approval of the Commission.
[...]
Annex - List one. Businesses stricto sensu not permissible to foreigners by special reason:
1. The Press, radio broadcasting station or radio and television station business[...]"((Foreign Business Act, B.E. 2542 (1999))
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"Section 4. In this Act: [...]
“newspaper” means a printed matter which has the same name thereon and is issued or intended to be issued in continuing sequences, irrespective of whether the time interval is determined or whether there are continuous texts, and shall include a magazine, a journal and a similar printed matter which is called with other name; [...]
“newspaper proprietor” means a person who owns a newspaper business;
[...]  
Section 15. A newspaper proprietor who is a natural person, a printer or a publisher must have the qualifications and not be under any of the prohibitions as follows:
(1) being not less than twenty years of age; (2) being of Thai nationality; (3) having a regular domicile in the Kingdom; [...]" (Printing Recordation Act, B.E. 2550 (2007))
Foreign Business Act, B.E. 2542 (1999).
Printing Recordation Act, B.E. 2550 (2007).
[<a href="https://investmentpolicy.unctad.org/investment-laws/laws/40/thailand-foreign-business-act">Act</a>],[<a href="http://web.krisdika.go.th/data/outsitedata/outsite21/file/Printing_Recordation_Act_BE_2550_(2007).pdf">Act</a>]