Insperity, Inc. (NYSE:NSP) stock is about to trade ex-dividend in 4 days time. If you purchase the stock on or after the 6th of September, you won't be eligible to receive this dividend, when it is paid on the 23rd of September.

Insperity's next dividend payment will be US$0.30 per share, on the back of last year when the company paid a total of US$1.20 to shareholders. Based on the last year's worth of payments, Insperity has a trailing yield of 1.2% on the current stock price of $99.06. We love seeing companies pay a dividend, but it's also important to be sure that laying the golden eggs isn't going to kill our golden goose! So we need to investigate whether Insperity can afford its dividend, and if the dividend could grow.

Check out our latest analysis for Insperity

If a company pays out more in dividends than it earned, then the dividend might become unsustainable - hardly an ideal situation. Insperity paid out just 25% of its profit last year, which we think is conservatively low and leaves plenty of margin for unexpected circumstances. That said, even highly profitable companies sometimes might not generate enough cash to pay the dividend, which is why we should always check if the dividend is covered by cash flow. It paid out 21% of its free cash flow as dividends last year, which is conservatively low.

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 consistently growing earnings per share generally make the best dividend stocks, as they usually find it easier to grow dividends per share. If business enters a downturn and the dividend is cut, the company could see its value fall precipitously. That's why it's comforting to see Insperity's earnings have been skyrocketing, up 45% per annum for the past five years. Insperity earnings per share have been sprinting ahead like the Road Runner at a track and field day; scarcely stopping even for a cheeky "beep-beep". We also like that it is reinvesting most of its profits in its business.

Another key way to measure a company's dividend prospects is by measuring its historical rate of dividend growth. Insperity has delivered an average of 17% per year annual increase in its dividend, based on the past 10 years of dividend payments. It's great to see earnings per share growing rapidly over several years, and dividends per share growing right along with it.