1. Rolling-Window Instability Engine
The MVIE composite blends three structural metrics — Absorption Ratio (eigenvalue concentration of the correlation matrix), Instability Score (mean change in pairwise correlations) and Priority Drift (MST centrality rank drift). Each is measured on the latest 60 trading sessions, standardised against its own previous 252 sessions and mapped to 0–100:
Composite formula · pseudocode
# Pseudocode — MVIE composite (one rolling 60-session window)# C_t = Spearman correlation of the latest 60 sessions, C_b = the 60 beforeAR = sum(top_k_eigenvalues(C_t)) / trace(C_t) # k = max(1, ceil(0.20 * n))IS = mean(abs(C_t - C_b) over i != j)PD = footrule(rank(eigencentrality(MST(C_t))), rank(eigencentrality(MST(C_b)))) # normalised to [0, 1]# Each component against its own previous 252 sessions (min 63), never itselfz = (x_t - mean(x[t-252 .. t-1])) / std(x[t-252 .. t-1])s = clip(50 + z * 50/3, 0, 100)MVIE = (0.40*s_AR + 0.35*s_IS + 0.25*s_PD) / (sum of available weights)Regime thresholds:
- 0–60 GREEN — Stable absorption / correlation structure; centrality ranks steady
- 60–80 AMBER — PCA concentration or correlation drift rising; MST hub order shifting
- 80–100 RED — Systemic stress band; correlation breakdown and centrality drift elevated