Tags Circular No 15 SBV tightens corporate bond purchase by banks Tuesday, Jun 19, 2018 State Bank of Viet Nam has tightened regulations on corporate bond purchase by credit institutions and foreign bank branches. Viettel dominates domestic telecom market Thursday, Jun 18, 2015 Viettel has become the only telecommunications enterprise to have significant market power (SMP) in land mobile service in terms of phones, messaging, and the Internet.