Task: Question Answering
Input (English): Passage: In the opinion of Robin Fedden, a diplomat, and later Deputy General Secretary of the National Trust and author of the Trust's first guidebook for Chartwell, the house became "the most important country house in Europe". A stream of friends, colleagues, disgruntled civil servants and concerned military officers came to the house to provide information to support Churchill's struggle against appeasement. At Chartwell, he developed what Fedden calls, his own "little Foreign Office ... the hub of resistance". The Chartwell visitors' book, meticulously maintained from 1922, records some 780 house guests, not all of them friends, but all grist to Churchill's mill. An example of the latter was Sir Maurice Hankey, Clerk of the Privy Council, who was Churchill's guest for dinner in April 1936. Hankey subsequently wrote, "I do not usually make a note of private conversations but some points arose which gave an indication of the line which Mr Churchill is likely to take in forthcoming debates (on munitions and supply) in Parliament". A week later, Reginald Leeper, a senior Foreign Office official and confident of Robert Vansittart, visited Churchill to convey their views on the need to use the League of Nations to counter German aggression. Vansittart wrote, "there is no time to lose. There is indeed a great danger that we shall be too late".Churchill also recorded visits to Chartwell by two more of his most important suppliers of confidential governmental information, Desmond Morton and Ralph Wigram, information which he used to "form and fortify my opinion about the Hitler Movement". Chartwell was also the scene of more direct attempts to prepare Britain for the coming conflict; in October 1939, when reappointed First Lord of the Admiralty on the outbreak of war, Churchill suggested an improvement for anti-aircraft shells; "Such shells could be filled with zinc ethyl which catches fire spontaneously ... A fraction of an ounce was demonstrated at Chartwell last summer".In 1938, Churchill, beset by financial concerns, again considered selling Chartwell, at which time the house was advertised as containing five reception rooms, nineteen bed and dressing rooms, eight bathrooms, set in eighty acres with three cottages on the estate and a heated and floodlit swimming pool.  He withdrew the sale after the industrialist Henry Strakosch agreed to take over his share portfolio, which had been hit heavily from losses on Wall Street, for three years and pay off significant associated debts. 
Question: What financial institute did the man who owned Chartwell suffer heavy losses investing in?
Output (English): Wall Street.