Treasury yields see biggest dive since 1987’s Black Monday

Investors flocked in droves to the safety of Treasurys on Monday in a manner not seen since the days that followed the 1987 stock-market crash, after the sudden closure of two banks and decision by banking regulators over the weekend to fully protect their deposits.

The policy-sensitive 2-year Treasury yield BX:TMUBMUSD02Y plunged 55.6 basis points to 4.03% on Monday. That’s its biggest one-day decline since October 20, 1987 — an infamous period kicked off by “Black Monday,” when Dow industrials dropped 22.6% on Oct. 19…