"While a prominent overseas investment adds diversity to Bharti's businesses and cash flows, the financing and the debt requirements are of greater concern, especially since Bharti has budgeted capital expenditures of about $3.3 billion per annum," Yasmin Wirjawan and Anshukant Taneja, rating analysts at S&P wrote in a note on Friday. S&P rates Bharti Airtel's debt BBB-, the lowest investment-grade rating, with a stable outlook.