Since they say that all repurchased units will be "cancelled", it is likely just a tactic to manage share price, which often is a factor in access to credit, etc. Fewer shares -> less net quarterly distributions at the current dist rate -> easier to support that dist in the future. Also means any share holders "grow" their percentage ownership with each cancelled unit. Both aspects look like good management to bankers and any company insiders holding large blocks of units. Especially any holders of options (think employees with options packages as compensation) set at a strike price that is higher than current; they run the risk of having those expire worthless if the PPS doesn't recover.
Book value is simply liquidation value, estimated or claimed. It doesn't represent the ongoing "money making" aspects like existing contracts, repeat customers, market share, industry prospects and the like. So book value doesn't even pretend to value the future earnings potential of a company. Very few companies sell even or above their book value, although it sometimes happens. That again can be due to the accounting "techniques" allowed or required when estimating book value...
NRGY no matter what is still buying back shares for more than they would be worth if they were trading for at least book. If you want a company buying back shares that is accretive then look at ACAS whose book is about $5 more than what they are buying back shares for. Since NRGY shares are being bought back for less than book they are destroying value with each share repurchased and will make it harder to borrow in the future. In other words book value = $8.65 repurchase share = $21.88 roughly 2.5 times book. Basically instead of building value they are destroying it. At most 5 million shares repurchased reducing divi money needed by $7.5 milllion from $187 million roughly. They still have 120 million shares out at $1.50 divi or $180 million needed for divi, but they are now less 100 million. With all the growth in the oil and gas pipe line area I find it hard to believe that they could not find something that they could buy that would be accretive to earnings and grow their way out of not covering their divi. I see reductions in divi coming. And if I remember right they said that they would reduce the divi to $1.20 a year once the sale was completed. If this is true then $1.20 divided by 21.88 equals 5.5%, too low for a non growing company. Should be around 8%+ or $15 max stock value.
Don't forget darnoc that you are getting the dividends from the SPH shares which are yielding more than NRGY. Also, you can't put any store in the book value of ACAS because it is based on management's best guess for their private companies. If you held ACAS during the market crash you would find that ACAS's assets were overvalued and illiquid. I wouldn't touch that stock which went from 50 to .50 in a short period of time. NRGY has real assets which are worth far more than book value.