ANZ has followed Westpac and NAB in buying back Commonwealth government guaranteed bonds with approximately one year left until maturity.With the major banks continuing to pay a guarantee fee of 70 basis points per annum, it is now cheaper to buy back these bonds than leave them outstanding.In an announcement to the ASX, ANZ advised it had bought back A$1,003,620,000 of floating-rate and A$1,361,154,000 of fixed-rate bonds, with a 16 January 2014 maturity date. There were A$2.4 billion and A$1.1 billion of the bonds outstanding prior to the buyback offer opening last Monday.ANZ paid only a slight premium to buy back the bonds early, and this might explain why A$1.0 million of the fixed-rate bonds remain outstanding. The bonds are paying a coupon of 5.25 per cent per annum with a government guarantee.ANZ paid 102.017 per cent of the face value to buy back the floating rate bonds and 104.760 per cent of the face value of the fixed-rate bonds. The bonds were trading at 101.7 per cent and 104.632 per cent, respectively, in the secondary market immediately prior to the offer being made, according to Yieldbroker.NAB bought back A$2.84 billion of government guaranteed bonds in early November, and Westpac bought back A$3.4 billion a few days later. This leaves only CBA with any significant capacity to undertake such a buyback. Subject to any buybacks that might have been quietly undertaken, CBA has A$2.8 billion of December 2013 and A$2.5 billion of February 2014 government guaranteed bonds outstanding.