Question: When was the merger of Fiat S.p.A. into a new holding company, FCA  became effective?

Context paragraphs:
Fiat Chrysler Automobiles: Fiat Chrysler Automobiles N.V. (abbreviated as FCA) is an Italian-controlled multinational corporation incorporated in the Netherlands, and currently the world’s seventh-largest auto maker.  The group was established in late 2014 by merging Fiat S.p.A. into a new holding company, FCA (with headquarters in London) for tax purposes.  The holding company is listed on the New York Stock Exchange and Borsa Italiana in Milan.  Exor S.p.A, an Italian investment group controlled by the Agnelli family, owns 29.19% of FCA and controls 44.31% through a loyalty voting mechanism.

Fiat Automobiles: Fiat Automobiles S.p.A. (FIAT, Italian: "Fabbrica Italiana Automobili Torino" , 'Italian Automobiles Factory, Turin' ) is the largest automobile manufacturer in Italy, a subsidiary of FCA Italy S.p.A., which is part of Fiat Chrysler Automobiles.  Fiat Automobiles S.p.A. was formed in January 2007 when Fiat reorganized its automobile business, and traces its history back to 1899 when the first Fiat automobile was produced.  Fiat has also been involved in weapons manufacture such as the Fiat–Revelli Modello 1914

Fiat S.p.A.: Fiat S.p.A., or "Fabbrica Italiana Automobili Torino" (Italian Automobile Factory of Turin), was an Italian holding company whose original and core activities were in the automotive industry, and that was succeeded by Fiat Chrysler Automobiles NV (FCA).  The Fiat Group contained many brands such as Ferrari, Maserati, Fiat, Alfa Romeo, the Chrysler Group, and many more.  On 29 January 2014, it was announced that Fiat S.p.A. (the former owner of Fiat Group) was to be merged into a new Netherlands-based holding company Fiat Chrysler Automobiles NV (FCA), took place before the end of 2014.  Fiat Chrysler Automobiles became the new owner of Fiat Group.  On 1 August 2014, Fiat S.p.A. received necessary shareholder approval to proceed with the merger (which followed board approval).  The merger became effective 12 October 2014.

Mekong Auto: Mekong Auto Corporation headquartered in Ho Chi Minh City, Vietnam, is a car manufacturer and assembler founded in 1991.  The first car was built at the Delta Auto Plant on May 20, 1992.  Japanese Saeilo Machinery Japan Inc. is the major shareholder of the company, owning 51%.  The company opened Co Loa Auto Plant in Ha Noi City in 1993.  The company works with Fiat S.p.A. (Fiat cars and Iveco trucks), Pyeonghwa Motors and SsangYong.

Teksid: Teksid (Teksid S.p.A.) is an Italian company based in Carmagnola which specialises in the production of iron and castings for the automotive industry.  Originally known as Ferriere Piemontesi, Teksid is owned by Fiat Chrysler Automobiles, and was owned its predecessor Fiat S.p.A. since 1917.  The company was renamed Teksid in January 1978.

Fiat Industrial: Fiat Industrial S.p.A. was an Italian company into which Fiat S.p.A. (parent company of Fiat Group) demerged most of its activities not directly related to automobiles at the start of 2011.  Fiat Industrial served as a holding company for the activities of truck manufacturer Iveco; an 89.3% stake in the agricultural and construction equipment producer CNH Global; and FPT Industrial, which consists of the industrial and marine activities formerly part of Fiat Powertrain Technologies.  The company's Chairman was Sergio Marchionne, who also served as CEO of Fiat S.p.A. and Chairman/CEO of Chrysler Group LLC, now merged as Fiat Chrysler Automobiles.

FCA Bank: FCA Bank, a joint venture between Fiat Chrysler Automobiles Italy S.p.A. and Crédit Agricole Consumer Finance S.A is a bank dedicated to motorists, which mainly operates in the automotive financing sector and cooperates with prestigious automotive brands (Alfa Romeo, Chrysler, Fiat, Fiat Professional, Jeep, Abarth, Maserati, Jaguar and Land Rover) as well as motorhome and caravan manufacturers.

CNH Global: CNH Global NV was the holding company for the Italian public multinational manufacturer of agricultural and construction equipment, established on November 12, 1999, through the merger of Case and New Holland.  Effective 29 September 2013, CNH Global N.V. and Fiat Industrial S.p.A. were merged into CNH Industrial N.V.

Alfa Romeo Pomigliano d'Arco plant: The Alfa Romeo Pomigliano d'Arco plant, commonly known as the Alfasud Pomigliano and renamed in 2008 as "Giambattista Vico" in memory of the Neapolitan philosopher, is a car factory, situated in the town of Pomigliano d'Arco, and partly in Acerra.  The factory is nowadays owned by the Fiat S.p.A. Designed in 1968 by Alfa Romeo, the factory began car production in 1972.  Today the plant has about 6,000 employees.  The last Alfa Romeo model produced in Pomigliano was the Alfa Romeo 159 on 28 October 2011, the factory was converted to build the new Fiat Panda.

Fiat-Sollers: Fiat-Sollers (Russian: СП «Соллерс-Fiat» ) was a joint venture between Fiat S.p.A. and Sollers JSC (formerly Severstal Avto).  Each company had a 50% share in the venture, and the product range was determined by Fiat.

Supporting paragraphs: Fiat Chrysler Automobiles Fiat S.p.A.
Answer: 12 October 2014