If you are an income investor, you want a portfolio full of companies with sustainable dividends, the S&P 500'sDividend Aristocrats is a good place to start, explains Robert Rapier, editor of Utility Forecaster.

By definition, a Dividend Aristocrat must be in the S&P 500 index and have recorded dividend increases for at least the past 25 consecutive years. A company must also meet certain market capitalization and liquidity requirements to appear on the list.

You might expect that companies that have raised their dividends for at least 25 consecutive years would have attractive yields. That is incorrect for the most part. Most of the companies on the list have yields that are low for dividend investors. That’s because investors tend to bid up companies that are consistent long-term performers.

Payout ratio is an important metric over time because it signals whether a dividend is sustainable from cash flow. It may not be a problem for a company to go over 100% on the payout ratio for brief periods of time. A consistently high payout ratio, however, is a sign that the dividend isn't sustainable.

Among the 64 companies on the current list, 44 yield less than 3%. The average yield for the entire list is 2.7%. But that’s still better than the S&P 500, which presently yields only 1.8%. However, the following six companies on the list currently yield at least 5%.

Global apparel and footwear company VF Corp. (VFC), which makes well-known brands like JanSport, Eastpak, Timberland, and North Face, is the highest-yielder on the list at 6.9%. It has raised its dividend for 50 consecutive years.

Walgreens Boots Alliance (WBA) is the largest retail pharmacy in both the United States and Europe. The company currently yields 5.8%, and has raised its dividend for 46 consecutive years.

International Business Machines Corp. (IBM) is the highest-yielding Dividend Aristocrat right now. The company currently yields 5.5%, and has raised its dividend for 26 consecutive years.

Realty Income Corporation (O) is a real estate investment trust that invests in free-standing, single-tenant commercial properties in the United States, Spain and the United Kingdom. It currently yields 5.4%, and has raised its dividend for 27 consecutive years.

Franklin Resources, Inc. (EN) is a global investment firm that, together with its subsidiaries, is referred to as Franklin Templeton. It currently yields 5.3% and has raised its dividend for 41 consecutive years.

3M Co. (MMM) is a multinational conglomerate operating across multiple fields. It is one of the oldest of the Dividend Aristocrats. It currently yields 5.2% and has raised its dividend for an amazing 64 consecutive years.

I will close with the standard caveat that companies with the highest yields are also those at greatest risk of falling off the Dividend Aristocrats. A high yield generally means a decline in the underlying stock price. AT&T (T) was the most recent example, as it came off the list this year.

Nevertheless, these are companies that have managed to raise their dividends during good times and bad, and are therefore pretty good bets for weathering future economic storms. For those interested in investing in the entire list of Dividend Aristocrats, there are multiple exchange-traded funds (ETFs) based on the list.

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