The trading volumes are not big.  We are likely seeing  arbitrage play mostly.  Sell a share of PBN buy a share of PBG.  Around the end of December you will get back 1.1 shares of PBN and  a "new PBG" share  with $1 cash, the heavy oil lands, Thai assets, and the intellectal property of Arcon.  And you only miss one month's dividends.  Not a bad trade if your transaction costs are low.