CFDs are complex instruments and come with a high risk of losing money rapidly due to leverage. 70.96% of retail investor accounts lose money when trading CFDs with this provider. You should consider whether you understand how CFDs work and whether you can afford to take the high risk of losing your money.

What is the underlying asset?

The "underlying asset" is the instrument that a CFD is based on. For example, the underlying asset for the SPX500 is the S&P 500 Index of US stocks.