The blunt, emotional resignation letter by Infosys (INFY) CEO Vishal Sikka cites the difficulties the information technology consulting company has faced in doing business in the United States while addressing significant internal conflicts.

Infosys shares had slumped 7.7% in recent U.S. trading, while the iShares MSCI India exchange-traded fund (INDA) was up 0.5%

Chief...