Think of it this way: If you want to calculate how much money you have made in 2021, you start at zero, and then Jan. 1’s data is the first “change.” You don’t start counting on Jan. 2.
(And while we are on the topic, the stylebook notes that we use hyphens only when the phrase precedes the noun: year-to-date expenses. Otherwise: expenses for the year to date. Use the abbreviation YTD only in tabular material.)
Notes on the News
The news of the week in context, with Tyler Blint-Welsh.
This is similar to an issue we used to sometimes have with reporting on the performance of new stock offerings. The rise in a new stock must be calculated from the offering price (the price that was set on the initial public offering), not on the first trade or the first day’s close. Otherwise, we are capturing only a part of the true movement in the stock from its base price.