The Reserve Bank of India (RBI) has permitted transfer of and trading in power bonds maturing on October 1, 2008 and April 1, 2009, issued by various states to central public sector undertakings.These bonds were issued in terms of a tripartite agreement among the 27 state governments, the union power ministry and the RBI under the one-time settlement of dues of state electricity boards."As per the agreement, these bonds were to be released for trading in a phased manner," RBI said in a release today.