Some of the leading closed-end funds returned as much as 13% in August, with four of the top 10 exposed to the energy sector in one form or another. All this with a pullback in the price of oil.

The key seems to be non-diversification -- that is, focus on a few quality companies. For the top three funds, 50% to 60% of total assets are invested in their top 10 holdings.

The funds also share many common stock holdings.

The top holdings common to all three funds include

Kinder Morgan Management

(KMR)

,

Enterprise Products Partners LP

(EPD) - Get Report

,

Plains All American Pipeline LP

(PAA) - Get Report

and

Energy Transfer Partners

(ETP)

.

The top funds follow below.

Sam Patel, CFA, is the manager of mutual fund research for the TheStreet.com Ratings.

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