I know that Apple, for example, began paying dividends in 2012. Can a company do the opposite, namely stop paying dividends suddenly?
Yes. Companies increase, decrease, start paying and stop paying dividends when they think it appropriate.
If a company has been going through some problems and makes a loss, or even a large decrease in profits, they can choose to stop paying dividends until things improve. Many companies did this during the Global Financial Crisis of 2007-08.
Dividends are supposed to be paid from company profits (in the current or previous financial years), there are nuances around what profits mean from country to country, but the link is the UK definition from the HMRC. Profits from previous financial years are commonly called retained earnings.
There are a few items around this
- If the company is not currently profitable and has no retained earnings, there will be no dividend
- If the company is currently profitable or has retained earnings, they will usually choose to reinvest a certain proportion of their profits back into the business for development. This is discretionary.
- If the company is currently profitable or has retained earnings, there can be multiple classes of share (in some countries) that attract different levels of dividend, so again you may have a class "B" share that gets no dividend, while the class "A" shares receive a dividend.
- If the company is currently profitable or has retained earnings, then finally, the class of share you have may get a dividend.