Six leading banks in Kazakhstan saw some of their credit ratings downgraded on Thursday by Moody’s Investors Service as concerns mounted over a liquidity crisis in a sector which is heavily exposed to turbulent global credit markets.

Kazakh banks have borrowed heavily in recent years to finance a consumer spending boom driven by the republic’s newfound oil wealth. Moody’s estimates that Kazakh banks’ total borrowings amount to $40bn, accounting for over half their non-equity funding. However, the international credit squeeze has made refinancing mature debt more difficult. This has also raised concerns about the potential impact on the economy.