Britain leaves the gold standard, and the pound sterling depreciates by 25%. Despite warning of disaster, the departure proves beneficial to the British economy, as exports become more competitive. Additionally, the Bank of England was now free to engage in money creation, and reduced interest rates from 6.00% to 2.00%.
On 21 September, with the head of the column at the town of Maqueda (some 80 km away from Madrid), Franco ordered a detour to free the besieged garrison at the Alcázar of Toledo, which was achieved on 27 September.
On 21 September it was decided that Franco was to be commander-in-chief (this unified command was opposed only by Cabanellas), and, after some discussion, with no more than a lukewarm agreement from Queipo de Llano and from Mola, also head of government. Emilio Mola y Vidal, 1st Duke of Mola, Grandee of Spain was one of the three leaders of the Nationalist coup of July 1936, which started the Spanish Civil War.
On the Nationalist side, Franco was chosen as chief military commander at a meeting of ranking generals at Salamanca on 21 September, now called by the title Generalísimo.
In November 1939, the United States was taking measures to assist China and the Western Allies, and amended the Neutrality Act to allow "cash and carry" purchases by the Allies. Cash and carry was a policy by US President Franklin Delano Roosevelt announced at a joint session of the United States Congress on September 21, 1939, subsequent to the outbreak of war in Europe. It replaced the Neutrality Acts of 1937, by which belligerents could purchase only nonmilitary goods from the United States as long as the recipients paid immediately in cash and assumed all risk in transportation using their own ships.
Allied troops in Saigon were an airborne detachment, two British companies of the Indian 20th Infantry Division and the French 5th Colonial Infantry Regiment, with British General Sir Douglas Gracey as supreme commander. The latter proclaimed martial law on September 21. The following night the Franco-British troops took control of Saigon.
On 22 September, a prolonged battle began in the city of Khorramshahr, eventually leaving 7,000 dead on each side. Reflecting the bloody nature of the struggle, Iranians came to call Khorramshahr "City of Blood".
Iraq launched a full-scale invasion of Iran on 22 September 1980. The Iraqi Air Force launched surprise air strikes on ten Iranian airfields with the objective of destroying the Iranian Air Force. The attack failed to damage the Iranian Air Force significantly; it damaged some of Iran's airbase infrastructure, but failed to destroy a significant number of aircraft.
September 21, 2008: Goldman Sachs and Morgan Stanley converted themselves from investment banks to bank holding companies to increase their protection by the Federal Reserve.
On 21 September 2017, Google announced that it would acquire roughly half of the 4,000 employees who worked in HTC's design and research staff, and non-exclusive licenses to smartphone-related intellectual property held by HTC, for US$1.1 billion. The employees included the team involved with Google's Pixel smartphone, which was manufactured by HTC. Google stated that the purchase was part of its efforts to bolster its first-party hardware business. The transaction was completed on 30 January 2018; while HTC will continue to produce its own smartphones, the company has stated that it planned to increase its focus on the Internet of Things (IoT) and virtual reality going forward.