See “Market Tremors. Excerpt:
The Nikkei 225 index fell 17.5% in the three trading days following the catastrophe, wiping some ¥37 trillion ($458 billion) off equities. This compares unfavourably with market reactions to other disasters. Once the New York Stock Exchange had reopened six days after the September 11th terrorist attacks, the S&P 500 fell by 11.6% over five trading days, but after a further 14 days it had recovered to its pre-disaster level.