Werner von Siemens retired in 1890, while Johann Georg Halske had already left the company in 1867. Werner von Siemens' brother Karl Heinrich, together with Werner's sons Arnold and Georg Wilhelm, grew the firm and erected new Siemens & Halske premises along the banks of the western Spree river, in the Berlin suburb of Charlottenburg, in 1897. The firm's vast new site continued to grow, and from 1899 onwards it was known as Siemensstadt.
When Siemens & Halske merged parts of its activities with Schuckert & Co., Nuremberg in 1903 to become Siemens-Schuckert, Siemens & Halske AG specialized in communications engineering. During World War I, rotary engines of advanced and unusual design were produced under the Siemens-Halske brand, like the Siemens-Halske Sh.I and Sh.III. Later, Siemens established several company subsidiaries for which the Siemens & Halske AG functioned as a holding company.
During the Second World War, Siemens & Halske employed slave labour from concentration camps.