My broker said I'd made $18,000. The number was an aggregate over a query nobody could show me.

The number sat on my broker's home screen, green, precise to two decimals. Roughly eighteen thousand dollars, earned from investing, over the whole period I'd been at it. I looked at it for a long time and realised I didn't know what it included. Dividends — reinvested ones, or only the ones that landed as cash? Before or after the tax withheld in...