investors flocked in droves to the safety of treasurys on monday in a manner not seen since the days that followed the 1987 stockmarket crash after the sudden closure of two banks and banking regulators stepping in over the weekend to fully protect their deposits the policysensitive 2year treasury yield bxtmubmusd02y briefly fell below 4 earlier monday and headed for its biggest threeday decline since oct 22 1987 an infamous period that was kicked off by “black monday” when dow industrials dropped 226 on oct