6.5 million according to some membership trading co
This is only for those with low face value.
The lowest asking price in market is about $6.3 million for the lowest face value ones ($200k). For those with high face value, the price is much higher.
The record transacted price so far is a whopping $8 million for one with a face value of 3 million back in August (the "peak season" when people are rushing to snap up debentures before next year's application opens in Sept/Oct.