Commerce; Financial markets; Rare earths; Transmitters; Wavelet analysis; Comovement; Energy indexes; Rare-earths; REMX rare earth index; Renewable energies; Renewable energy index; Return and volatility spillover; Spillover index methodology; Volatility spillovers; Wavelet based analysis; alternative energy; COVID-19; index method; rare earth element; solar power; spillover effect; stock market; wind power; Renewable energy indices; Return and volatility spillovers; Wavelet-based analysis