AAFLAFLAC Incorporated

Aflac sells supplemental health insurance, and its Japanese half is larger than its American one.

The product is not a replacement for primary health insurance but a supplement: a cash payment on a cancer diagnosis, hospitalisation or injury, covering what the primary policy does not. Policies are inexpensive, sold through employers and retained for years.

The Japanese business is historically larger than the American one and sets the result. Hence the stock's defining feature: a large share of profit arrives in yen, and a stronger dollar directly reduces it in the accounts regardless of how the business itself performs.

A second feature is reserve investment: much of the portfolio sits in Japanese government bonds at very low yields, and rising Japanese rates change the company's economics. Aflac is a dividend aristocrat with a long record of increases.