Figure 13.
The four panels labelled a to d show wavelet coherence between C P U index and D J S U K B, S B K U O P, I 3 0 7 4 0 U S and I 3 8 3 1 0 indices. The horizontal axis spans June 2013 to September 2024, and the vertical axis shows a scale from 4 to 1024. Strong coherence appears as highlighted regions mainly at mid to large scales around 2014 to 2018 and again near 2022 to 2024. High-frequency regions show weaker scattered coherence. Arrow directions vary across regions, indicating changing relationships over time.Continuous wavelet transform correlation of CPU versus four sukuk indices (2013–2024)
Note(s): The region above the cone of influence (delineated by the parabola in gray color) shows the statistically significant areas in the scalogram. DJSUKB Index is the Dow Jones Sukuk AP FIGI BBG003TNNKV7 Index; SBKU0P Index is FTSE Sukuk Index 10 + Yr USD; I30740US Index is Bloomberg EM GCC USD Sukuk Total Return Index Unhedged USD; I38310 Index is Bloomberg Global Agg Sukuk Unh USD
Source: Authors’ own work; see data section for sources