Identifying the comovement of price between China's and international crude oil futures: A time-frequency perspective

摘要

Identifying the comovement of price between China's and international crude oil futures can help different market players gain a deeper understanding of the world crude oil market. This paper uses the wavelet (wavelet coherence and phase) methods to study the comovement characteristics at different time scales from three aspects (the strength of comovement, the direction of comovement and the lead-lag relationship of price fluc-tuation) and uses the complex network method to explore the evolutionary characteristics of the comovement with time. We use the daily closing prices of WTI, Brent and China's crude oil futures (INE) as sample data. The results show that the comovement between INE and international crude oil futures is extremely different from that between other international crude oil futures, and the comovement at different time scales is also different. Compared with the comovement between WTI and Brent crude oil futures, the comovement strength between INE and international crude oil futures is weak and the comovement direction is unstable. China's crude oil futures price fluctuation also tends to lag behind that of international crude oil futures. Compared with the longterm, the short-term comovement strength is weaker, the comovement states are more diverse and the transition between comovement states is more complex. Moreover, during the evolution of time, some comovement states have a higher probability of occurrence and they are also more stable than others. These findings are helpful for policy makers to design policies and for investors to make investment decisions.