I thought they have 60 days to report trades [1] and there are a bunch of stock-based investments that explicitly don't require reporting (EIF's)? Sure, if somebody decides to voluntarily file on day 1, or buy stock "raw" that's cool, but in general there should be quite significant lag or gaps (to the point where short/medium-term there's no signal basically).

[1] https://ethics.house.gov/sites/ethics.house.gov/files/docume...