World War II had a significant impact on the company with many of its factories being destroyed by Allied bombing raids, and discord after the war. Founder Odaira was removed from the company and Hitachi Zosen Corporation was spun out. Hitachi's reconstruction efforts after the war were hindered by a labor strike in 1950. Meanwhile, Hitachi went public in 1949.
Hitachi America, Ltd. was established in 1959. Hitachi Europe, Ltd. was established in 1982.
From 2006 to 2010, Hitachi lost US$12.5 billion, the largest corporate loss in Japanese history. This prompted Hitachi to restructure and sell a number of divisions and businesses, a process that is expected to finish in 2021.
In January 2012, Hitachi announced it would stop producing televisions in Japan. In September 2012, Hitachi announced that it had invented a long-term data solution out of quartz glass that was capable of preserving information for millions of years. In October 2012, Hitachi agreed to acquire the United Kingdom-based nuclear energy company Horizon Nuclear Power, which plans to construct up to six nuclear power plants in the UK, from E.ON and RWE for £700 million. In November 2012, Hitachi and Mitsubishi Heavy Industries agreed to merge their thermal power generation businesses into a joint venture to be owned 65% by Mitsubishi Heavy Industries and 35% by Hitachi. The joint venture began operations in February 2014.
In October 2015, Hitachi completed a deal with Johnson Controls to form a joint-venture that would takeover Hitachi's HVAC business. Hitachi maintained a 40% stake of the resulting company, Johnson Controls-Hitachi Air Conditioning. In May 2016, Hitachi announced it was investing $2.8 billion into its IoT interests.
Following the Fukushima Daiichi nuclear disaster in 2011 and the extended temporary closure of most Japanese nuclear plants, Hitachi's nuclear business became unprofitable and in 2016 Hitachi CEO Toshiaki Higashihara argued Japan should consider a merger of the various competing nuclear businesses. Hitachi is taking for 2016 an estimated ¥65 billion write-off in value of a SILEX technology laser uranium enrichment joint venture with General Electric.
In February 2017, Hitachi and Honda announced a partnership to develop, produce and sell motors for electric vehicles. On March 14, 2018, Zoomdata announced its partnership with Hitachi INS Software to help develop big data analytics market in Japan.
In December 2018, Hitachi Ltd. announced it would take over ABB Ltd.'s power grid division for $6.4 billion. Also in 2017, private equity firm KKR bought Hitachi Kokusai's (itself a subsidiary of Hitachi) semiconductor equipment division, becoming Kokusai Electric. In 2019, Applied Materials announced that it would acquire Kokusai Electric from KKR for US$2.2 billion.
From 2008 to 2018, Hitachi has reduced the number of its listed group companies and consolidated subdiaries in Japan from 22 to 4 and around 400 to 202, respectively, through restructuring and sell-offs. It planned to become a company specialized in IT and infrastructure maintenance in the near future.
In 2019, Hitachi sold its medical imaging business to Fujifilm for US$1.7 billion. Showa Denko bought Hitachi Chemical from Hitachi and other shareholders, at US$42.97 per share. Until then, Hitachi Chemical had been considered to be a core unit of the group. Hitachi also suspended the ABWR development by its British subsidiary Horizon Nuclear Power as it did not provide an adequate "economic rationality as a private enterprise" to proceed.
In October the same year, Honda was reported to be in talks with Hitachi to merge the two companies' car parts businesses, creating a components supplier with almost $17 billion in annual sales, the second largest among the Japanese car parts companies. Hitachi retained the control of the new company with a 67 percent stake.
In September 2020, Hitachi pulled the plug on plans to create nuclear power plants in Gloucestershire and Wales due to issues with funding due to the impact of COVID-19.
Hitachi Vantara is a wholly owned subsidiary of Hitachi which provides hardware, software and services to help companies manage their digital data. Its flagship products are the Virtual Storage Platform (for enterprise storage), Hitachi Unified Storage VM for large-sized companies, Hitachi Unified Storage for small and mid-sized companies, Hitachi Content Platform (archiving and cloud architecture), Hitachi Command Suite (for storage management), Hitachi TrueCopy and Hitachi Universal Replicator (for remote replication), and the Hitachi NAS Platform.
Since September 19, 2017, Hitachi Data Systems (HDS) has become part of Hitachi Vantara, a new company that unifies the operations of Pentaho, Hitachi Data Systems and Hitachi Insight Group. The company name "Hitachi Data Systems" (HDS) and its logo is no longer used in the market.
Hitachi Consulting, the international management and technology consulting subsidiary with headquarters in Dallas, Texas, was integrated with Hitachi Vantara in 2019.
Among other things, Hitachi Metals supplies materials for aircraft engines and fuselage components (e.g. landing gear), along with finished components for same and other aerospace applications. It also provides materials, components and tools for the automotive and electronics industries.
In July 2020, Hitachi signed an exclusive agreement with Hyperdrive, a UK-based lithium-ion battery company, to bring battery-powered trains to the country.
Hitachi Works consists of three factories: Kaigan Works, Yamate Works, and Rinkai Works. Yamate Works, the oldest of the three factories, was founded in 1910 by Namihei Odaira as an electrical equipment repair and manufacturing facility. This facility was named Hitachi, after the Hitachi Mine near Hitachi, Ibaraki.
Hitachi Global Life Solutions - Manufacturing home appliances, air conditioners.
Hitachi Digital Media Group - Selling electronic products including video projectors under its brand name.
Hitachi Plant Technologies - Engaging in the design, development, manufacture, sale, servicing, and execution of social and industrial infrastructure machinery, mechatronics, air-conditioning systems, industrial plants, and energy plant equipment in Asia and internationally.
Hitachi Communication Technologies America - Providing communications products and services for the telecommunications, cable TV, utility, enterprise, industrial and other markets.
Hitachi Solutions America - A consulting firm and systems integrator focusing primarily on Microsoft Dynamics. Hitachi Solutions America acquired Ignify, a Microsoft Dynamics Solution provider, in December 2015.