Both U.S. and foreign stocks,

They concluded that such forecasting will be difficult. “Because of the infrequency and randomness of extreme market events, this prediction
is difficult to make with precision,” they wrote.4
The authors themselves chose two different responses.
Joaquin cut the global portion of his portfolio, which included
both U.S. and foreign stocks, to 20 percent from 40 percent.
“Foreign equities are not as reliable a cushion during market
downturns as I originally assumed [before the study],” Joaquin
said in an interview by e-mail. “And I can still take advantage of
profit opportunities in foreign markets indirectly by investing in
U.S. firms with substantial operations in other countries.