interesting

I suppose that as a sector fund one shouldn't expect it to be particularly well
diversified; it isn't. The average correlation of returns amongst the holdings is +52%
over the last four years, +46% if you include cash in the portfolio

During the last four years, 8 of the 20 holdings - CNX, DO, NFX, BTU, ACI, MEE, HAL and
BJS - have provided no useful diversification; i.e., any portfolio that contained any of
these could be improved - less risk for the same return or more return for the same risk -
by dropping these securities.

If the fund includes cash, the situation is even more severe: 12 of the 20 securities
provided no useful diversification. Those that did are CNX, RIG, PXP, MEE, SNSA, SWN,
OMM, and SLB.