BPT is now trading a 7 times it's annual yield of $10. The yield is not declining (production on the North Slope is declining overtime, but will last for at least another 18 years--perhaps more with slant drilling and fracking).
Rich people, who apparently own most of the 21 million shares, cannot sell this fast enough. They need to reduce their taxable income, before it goes to as high as 40% tax rate. This is understandable up to a point. But an 18 year annual income stream of $10, is worth well north of $72. At this price, BPT is the deal of the century