The universe of exchange-traded funds (ETFs) dedicated to environmental, social and governance (ESG) investing principles is growing, and some members of this ETF sub-section are coming of age. That includes the SPDR SSGA Gender Diversity Index ETF (SHE).

SHE, which tracks the SSGA Gender Diversity Index, debuted in March 2016, and as highlighted by more than $341 million in assets under management, it has gained traction with investors. Components in SHE's index are ranked by three gender diversity metrics, with the ETF's objective being "to provide exposure to U.S. companies that demonstrate greater gender diversity within senior leadership than other firms in their sector," according to State Street. (See also: Gender Lens Investing: Growing Interest, Increasing Options.)

SHE is up 12% year to date and 15.5% over the past year. Some historical data points and academic research suggest that companies with gender diversity on their boards and in the C-suite often outperform their less diverse counterparts.

SHE's underlying index "starts with largest 1,000 U.S. companies by market capitalization and ranks all stocks in each sector on three gender diversity ratios: 1) the ratio of female executives and board directors to all executives and board directors, 2) the ratio of female executives to all executives, and 3) the ratio of nonboard female executives to all nonboard executives," according to Morningstar. (See also: 5 Women Executives Who Are Shattering the Glass Ceiling.)

The SPDR SSGA Gender Diversity Index ETF allocates over 37% of its combined weight to the technology and healthcare sectors, the two best performing groups in the S&P 500 this year. The two consumer sectors combine for over 26% of the fund's weight. SHE's top 10 holdings include blue chips such as Pfizer Inc. (PFE), The Coca-Cola Company (KO) and McDonald's Corporation (MCD), all of which are members of the Dow Jones Industrial Average.

SHE practices what it preaches and extols some ESG virtues in the real world. The ETF "donates a portion of that revenue to SHE Impacts, a donor-advised fund that supports charitable organizations that prepare girls to become future business leaders," said Morningstar. "SHE Impacts provides grants to organizations that encourage girls to go into fields where women are poorly represented, such as science, technology, and math. It also supports programs that promote gender diversity in corporate leadership." (See also: These SRI Funds Focus on Empowering Women.)

Another perk with SHE is its expense ratio of just 0.2% per year, the equivalent of $20 on a $10,000 investment. That compares favorably with other large-cap smart beta and ESG strategies. Year to date, investors have added $36.3 million to SHE. (See also: Top 5 ETFs for Impact Investing for 2017.)

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