U.S. dockworkers at 14 ports stretching from Maine to Texas handling more than 68% of the country's imports started to strike, hurting most shipments at East and Gulf Coast ports and threatening to accelerate inflation through potentially snarled supply chains.

JPMorgan estimates the economic loss from the shutdown of every major container port from Houston to Miami and New York-New Jersey will be between $3.8 billion and $4.5 billion per day.