Shares of United Parcel Service Inc. slumped Monday as investors prepared for the package-delivery giant’s quarterly results, which have not been so kind to investors in the recent past.The company is slated to reveal its fourth-quarter earnings report on Tuesday at around 6 a.m. Eastern time. UPS’s stock has declined on the day that each of its past three reports were released by an average of 5.6%, and has fallen on the day of six of its past seven reports.UPS shares UPS, -1.04% dropped 1.6% in afternoon ...