Altair Engineering is a leading provider of software in the industrial simulation and analysis market and offers its products to the aviation, automotive and financial services sectors.
According to the agreement signed by Siemens, Altair shareholders will receive $113 (€103.97) per share, representing and enterprise value of approximately $10bn (€9.2bn).
The German multi-national said that the acquisition would strengthen its position as a technology company and also its leadership in industrial software.
The President and CEO of Siemens AG, Roland Busch, said in a statement: "Acquiring Altair marks a significant milestone for Siemens......The addition of Altair's capabilities in simulation, high performance computing, data science, and artificial intelligence together with Siemens Xcelerator will create the world's most complete AI-powered design and simulation portfolio."
Acquisition is a 'logical next step' for Siemens
Mr Busch added: "It is a logical next step: we have been building our leadership in industrial software for the last 15 years, most recently, democratising the benefits of data and AI for entire industries."
Commenting on the acquisition, the CFO of Siemens AG, Ralf P. Thomas said: "The acquisition of Altair is highly synergistic, underpinning Siemens' stringent capital allocation, balancing investments and shareholder returns on the basis of a strong balance sheet."
Altair's founder and CEO, James Scapa, said in a statement: "This acquisition represents the culmination of nearly 40 years in which Altair has grown from a startup in Detroit to a world-class software and technology company. We have added thousands of customers globally in manufacturing, life sciences, energy and financial services, and built an amazing workforce, and innovative culture.
"We believe this combination of two strongly complementary leaders in the engineering software space brings together Altair's broad portfolio in simulation, data science, and HPC with Siemens' strong position in mechanical and EDA design.
He added: "Siemens' outstanding technology, strategic customer relationships, and honest, technical culture is an excellent fit for Altair to continue its journey driving innovation with computational intelligence."