A 100 year-old stock market indicator is flashing bearish signals that point to more pain ahead for investors

• There is a bearish divergence developing between the Dow Jones Transportation Average and the Dow Jones Industrial Average.
• While the transports index made a higher high in January, the transportation average did not.
• Dow Theory is a more than 100-year old technical indicator that suggests if transportation companies are doing well, so should the broader economy. 

A more than century-old stock-market indicator is flashing a bearish signal that could mean more pain ahead for investors.