Boeing shares continued their slide Monday after explosive messages last week revealed a top pilot had concerns about a system on the 737 Max that was later implicated in two fatal crashes.

Several Wall Street analysts downgraded Boeing, fretting about the fallout from the crisis that has barred the manufacturer from delivering its best-selling planes that make up around 40% of its profit.

Boeing's stock fell 3.8% Monday to a two-month low of $331.06, shaving 88 points off the Dow Jones Industrial Average, but had pared losses from earlier in the session.

The messages made public Friday included an exchange from a top Boeing pilot to a colleague in 2016 that expressed his worries about an aggressive flight-control system on the Max, whose performance he called "egregious." The pilot, who now works for Southwest, said in the exchange that he "unknowingly" lied to regulators. That same pilot months later told the FAA to remove the system, known as MCAS, from pilot procedures and training materials.

The FAA said Boeing knew about the messages for months and scolded Boeing in a letter for not releasing the documents earlier. Boeing defended its training materials for the 737 Max, which regulators deemed safe in 2017, and said it told regulators on "multiple occasions" about the broadened capabilities of the now-questioned system.