What is Tier 0 News?
The highest-impact macro/geopolitical headlines — anything that breaks correlations.
Definition
Tier 0 = headlines that mechanically *force* repricing across asset classes: war declarations, central bank surprise actions, peg breaks, sovereign defaults, choke-point closures, energy supply disruptions, lockstep credit-event triggers. Tier 1 = important but factorable (CPI, NFP, earnings). Tier 2/3 = noise.
Why it matters for trading
- Tier 0 events break the assumption of stationary correlations. Backtests calibrated on non-Tier-0 data will misprice risk during them; using factor models without a Tier 0 gate is how funds blow up.
- Tier 0 headlines are *time-sensitive* in a way Tier 1 are not. The first 10-30 minutes of a Tier 0 print contain ~40% of the multi-day move. Latency matters; tier classification matters more.
- Misclassifying a Tier 1 as Tier 0 over-reacts. Misclassifying a Tier 0 as Tier 1 under-reacts. Calibration drift here is the most damaging silent failure mode in any news-aware system.