Regular readers will know that we love our dividends at Simply Wall St, which is why it's exciting to see StarHub Ltd (SGX:CC3) is about to trade ex-dividend in the next three days. The ex-dividend date is usually set to be one business day before the record date which is the cut-off date on which you must be present on the company's books as a shareholder in order to receive the dividend. The ex-dividend date is of consequence because whenever a stock is bought or sold, the trade takes at least two business day to settle. Meaning, you will need to purchase StarHub's shares before the 21st of August to receive the dividend, which will be paid on the 6th of September.

The company's next dividend payment will be S$0.03 per share, and in the last 12 months, the company paid a total of S$0.084 per share. Based on the last year's worth of payments, StarHub has a trailing yield of 6.6% on the current stock price of S$1.28. If you buy this business for its dividend, you should have an idea of whether StarHub's dividend is reliable and sustainable. We need to see whether the dividend is covered by earnings and if it's growing.

See our latest analysis for StarHub

Dividends are typically paid from company earnings. If a company pays more in dividends than it earned in profit, then the dividend could be unsustainable. It paid out 78% of its earnings as dividends last year, which is not unreasonable, but limits reinvestment in the business and leaves the dividend vulnerable to a business downturn. We'd be worried about the risk of a drop in earnings. A useful secondary check can be to evaluate whether StarHub generated enough free cash flow to afford its dividend. Fortunately, it paid out only 43% of its free cash flow in the past year.

It's encouraging to see that the dividend is covered by both profit and cash flow. This generally suggests the dividend is sustainable, as long as earnings don't drop precipitously.

Click here to see the company's payout ratio, plus analyst estimates of its future dividends.

Have Earnings And Dividends Been Growing?

Companies with falling earnings are riskier for dividend shareholders. Investors love dividends, so if earnings fall and the dividend is reduced, expect a stock to be sold off heavily at the same time. StarHub's earnings per share have fallen at approximately 5.2% a year over the previous five years. Such a sharp decline casts doubt on the future sustainability of the dividend.

Many investors will assess a company's dividend performance by evaluating how much the dividend payments have changed over time. StarHub's dividend payments per share have declined at 8.3% per year on average over the past 10 years, which is uninspiring. While it's not great that earnings and dividends per share have fallen in recent years, we're encouraged by the fact that management has trimmed the dividend rather than risk over-committing the company in a risky attempt to maintain yields to shareholders.