Siemens was founded on October 1, 1847, by Werner von Siemens and Johann Georg Halske in Berlin, Germany. Werner von Siemens, a Prussian military officer and inventor, had developed an improved telegraph system and partnered with Halske, a precision mechanic, to commercialize it. The company's first major project was building a telegraph line from Berlin to Frankfurt in 1848, establishing Siemens as a pioneer in electrical communications infrastructure.
Throughout the second half of the 19th century, Siemens expanded rapidly across Europe and internationally, building telegraph networks across Russia, the Middle East, and India. The company developed the first electric streetcar in 1881 in Berlin and built some of the world's first electric power stations. Werner von Siemens also invented the dynamo-electric machine in 1866, a foundational contribution to electrical engineering.
By the early 20th century, Siemens had become one of Germany's largest industrial companies, operating in power generation, telecommunications, lighting, and transportation. The company merged with Schuckertwerke, an electrical manufacturer, in 1903 to form Siemens & Halske and Siemens-Schuckertwerke, which were later consolidated into Siemens AG in 1966.
During World War II, Siemens operated under the Nazi regime and used forced labor from concentration camps in its factories. The company has acknowledged this history and established a historical foundation to document and research this period. After the war, Siemens relocated its headquarters from Berlin to Munich and rebuilt its operations in West Germany.
Throughout the Cold War era, Siemens expanded globally, establishing manufacturing and sales operations across Europe, the Americas, and Asia. The company diversified into computers, semiconductors, and telecommunications equipment in the 1970s and 1980s, though it later divested many of these businesses as it refocused on its core industrial strengths.
In the 1990s and 2000s, Siemens underwent significant portfolio restructuring. The company spun off its semiconductor business as Infineon Technologies in 1999 and its mobile phone business as BenQ Mobile in 2005. Siemens acquired Dade Behring, Diagnostic Products Corporation, and other medical technology companies to build what became Siemens Healthineers.
In 2020, Siemens spun off its energy business as Siemens Energy AG, a separately listed company in which Siemens retained a minority stake. The spin-off reflected a strategic decision to focus the core Siemens business on industrial automation, smart infrastructure, and mobility rather than energy generation and transmission.
Roland Busch became President and CEO in February 2021, succeeding Joe Kaeser. Busch has accelerated the company's focus on industrial software and AI, including the announced acquisition of Altair Engineering, a simulation and AI software company, for approximately $10 billion, which was pending regulatory approval as of early 2025.