Ask what large companies did: deals, restructurings, impairments, cyber incidents, bankruptcies, delisting notices, accounting warnings and leadership changes. Set it against the economy (interest rates, employment, investment, prices) or against how their shares did afterward.
Every number comes from the data and is sourced: company filings, public economic series via FRED, and returns relative to the sector derived from market data (no share prices). When the data can’t answer a question, the Analyst says so.