The new Shanghai Stock Exchange (SSE) is a Chinese stock exchange based in the city of Shanghai and the largest in Mainland China. The current exchange is re-established on November 26, 1990 and was in operation on December 19 the same year.
SSE new Founded Nov 26, 1990
SSE Operation: Dec 19, 1990 at 09:30 (-8) Shanghai
SSE Composite (Index), Jul 15, 1991
Regards
Mario

I will be in Shanghai shortly. Do you have the original foundation date at all?

Might have a wonder down.

Hi Coffee!!

I have this:
The formation of the International Settlement (foreign concession areas) in Shanghai as a result of the Treaty of Nanking of 1842 (which ended the First Opium War) and subsequent agreements between the Chinese and foreign governments are crucial to the development of foreign trade in China and of the foreign community in Shanghai. The market for securities trading in Shanghai begins in the late 1860s. The first share list appeared in June 1866 and by then Shanghai's International Settlement had developed the conditions conducive to the emergence of a share market: several banks, a legal framework for joint-stock companies, and an interest in diversification among the established trading houses (although the trading houses themselves remained partnerships).

In 1891 during the boom in mining shares, foreign businessmen founded the "Shanghai Sharebrokers' Association" headquartered in Shanghai as China's first stock exchange. In 1904 the Association applied for registration in Hong Kong under the provision of the Companies ordinance and was renamed as "Shanghai Stock Exchange". The supply of securities came primarily from local companies. In the early days, banks dominated private shares but, by 1880, only the Hong Kong and Shanghai local banks remained.

Later in 1920 and 1921, "Shanghai Securities & Commodities Exchange" and "Shanghai Chinese Merchant Exchange" started operation respectively. An amalgamation eventually took place in 1929, and the combined markets operated thereafter as the "Shanghai Stock Exchange". Shipping, insurance, and docks persisted to 1940 but were overshadowed by industrial shares after the Treaty of Shimonoseki of 1895, which permitted Japan, and by extension other nations who had treaties with China, to establish factories in Shanghai and other treaty ports. Rubber plantations became the staple of stock trading beginning in the second decade of the 20th century.

By the 1930s, Shanghai had emerged as the financial center of the Far East, where both Chinese and foreign investors could trade stocks, debentures, government bonds, and futures. The operation of Shanghai Stock Exchange came to an abrupt halt after Japanese troops occupied the Shanghai International Settlement on December 8, 1941. In 1946, Shanghai Stock Exchange resumed its operations before closing again 3 years later in 1949, after the Communist revolution took place.
Have a good trip!!
Regards
Mario

Thank you for that. I will reply more later, but any exact date at all?
Otherwise I will have to rely on my own judgement.