C17.11. Shares of Pitney Bowes dropped 10 percent after it announced earnings per sharefromcontinuing operations of $0.70 forits September quarterof 1999, up from $0.49 in the same quarter in the year before. Revenues also increased 8 percent.

Analysts raised concerns about thequality of theearnings, citing a decrease in the fum's effective tax rate. Why might the effective tax rate be of concern to analysts?