S&P 500 dividend growth is slowing, and earnings for the benchmark U.S. equity index's member firms began contracting in late 2014. Combine that with geopolitical headwinds, concerns about valuations and other issues, and it's easy to see why investors are prizing low-volatility stocks with dependable dividend growth track records.

An exchange traded fund that comes to mind when seeking dependable dividend payers is the SPDR S&P Dividend ETF (NYSE: SDY), one of the largest U.S. dividend ETFs. The fund only holds stocks that a have a minimum dividend increase streak of 20 years. Due to the fact that the energy sector has been home to the bulk of negative U.S. dividend action for over a year, the sector's weight in SDY has dwindled to just over 3 percent.

Another critical element regarding dividend growth stocks is that these stocks perform notably less poorly during bear markets. According to State Street data, the average drawdown for the S&P 500 during its worst 15 months is almost 7.6 percent, but the average drawdown for SDY's underlying index during those months was less than 5.8 percent.

“The stock market is operating in an environment marked by a contentious geopolitical landscape, lofty valuations, and low corporate and economic growth,” said State Street Vice President David Mazza in a recent note. “Given this, we believe that risks are skewed to the downside, and dividends may contribute more to total return than price appreciation will. In this type of market, investors may want to consider dividend growers.”

Historical data indicate that while dividend stocks outperform over long holding periods, dividend growth stocks really outperform, particularly when investors reinvest those payouts.

Most importantly is what SDY attempts to do and how it does it. SDY aims to deliver steadily rising dividends by tracking the S&P High Yield Dividend Aristocrats Index, which mandates member firms have dividend increase streaks of at least 20 years.

SDY allocates over 24 percent of its weight to financial services stocks with industrial and utilities names combining for almost 29.5 percent. Consumer staples, another sector seen as a beacon of dependable dividend growth, is 13 percent of the ETF's weight.

“Dividend growers are U.S. companies that have a long history of consistently raising their dividends. While they may not have the highest yields, dividend growers can potentially offer investors exposure to disciplined companies that have endured difficult market and economic environments relatively well,” adds Mazza.