The thing to do is to get a real grip on what potential oil plays are on the properties, and don't forget that oil and gas production technology has radically changed lease potential in shale and tight gas formations.
Also don't forget that these are PRIVATE and not FEDERAL or STATE mineral properties and hydraulic fracturing and horizontal drilling might proceed at a faster pace than other trust properties, like SJT, PBT etc.
I really should just keep my mouth shut - here I am pumping an investment I wanted to own, and missed the boat when it was dirt cheep!
the only depletion is on my lack of research - any posters with insights please let us know if there are any Bony Springs formation plays on PBT holdings - or any other shale or tight sand oil producing formations they hold!
I have held PBT for 6 years and it has yielded about 6.8 percent avg divvy per year. From what i can read (sorta' between the lines,) they have at least 10 more years of petroleum reserves, so there is no immediate cause for concern. Its still a buy.
In the 10-K they report a production index in years by dividing remaining reserves by current production. The value reported for 2010 was 10 years, for 2009 it was 9.2 years. I couldn't find the production index in the 10-K's prior to 2009. I performed the calculation (FWIW) and came up with 2008=6.6yrs, 2007=8.8yrs, 2006=8.0yrs. I think this measure contains little useful information but apparently it makes some people feel better about something that is unknowable