Exchange traded funds that track utilities stocks have been among the best performing sector plays this year, but when looking through utilities ETF gains, investors might have noticed some slight differences.

For instance, the Guggenheim S&P Equal Weight Utilities ETF (NYSEArca: RYU) rose 13.2% year-to-date while the Utilities Select Sector SPDR (NYSEArca: XLU) increased 12.9%.

Unlike XLU, RYU includes a small allocation toward telecommunication services and follows an equal-weight methodology, writes Miriam Cross for Kiplinger.

The Guggenheim ETF has a 14.9% weight toward telecom stocks. Guggenheim argues that telecom stocks act more like utility stocks than the tech industry.

“The volatility, dividend yield and price-earnings ratio associated with telecom services are more closely aligned with the utility sector than with tech,” Guggenheim’s William Beldan said in the article.

Additionally, RYU follows an equal-weight indexing methodology where underlying holdings are more-or-less equally weighted. For example, Pepco Holdings (NYSE: POM) has a 3.6% weight in RYU, Frontier Communications (NasdaqGS: FTR) is 3.2% and Exelon Corporation (NYSE: EXC) is 3.1%. Last week, Exelon, the largest U.S. nuclear power provider and a top-10 holding in several of the largest utilities exchange traded funds, has agreed to purchase Pepco Holdings for $5.4 billion in cash. [Some ETF Ideas for the Exelon/Pepco Takeover]