New Delhi: Credit rating firm Fitch today affirmed Bharti Airtel's long-term foreign currency issuer default rating at 'BBB' with stable outlook, reflecting the firm's ability to repay debt. "Fitch Ratings has affirmed Bharti Airtel's (Bharti) long-term foreign currency issuer default rating (IDR) and senior unsecured rating at 'BBB'. The outlook on the IDR is stable," Fitch said in a statement. Credit ratings range from AAA, AA, A, BBB to D where the top rating includes high ability to replay debt and D indicates least. Fitch said Bharti's BBB rating reflects its established market leadership in the Indian wireless services industry with about 35 per cent revenue market share, diversified operations and holding of large pool of spectrum.