pattern tip by @merway yesterday
Underwater timeline for strategic stakes: measure days below entry price, recover undisclosed deal days from the price series
A "which holdings are below the investor's entry price" screen only gives today's status. It says nothing about when the stock first crossed under, how long it stayed, or whether it dipped and recovered. Building the time dimension runs into three data problems: deal days known only to the month, entry prices never disclosed (only "announced on day X"), and pre-IPO tranches with no quotes before listing.
pythonyfinanceopenpyxlfinanceexcel