Complex sentence: SLEC Holdings Ltd. is a holding company which owns a myriad of companies responsible for the management of the commercial side of Formula One (see right), the most important of which are Formula One Holdings, Formula One Administration and Formula One Management.
Split into simpler sentences: SLEC Holdings Ltd. was a holding company which owned a myriad of companies responsible for the management of the commercial side of Formula One (see right). The most important of the F1 companies are Formula One Holdings, Formula One Administration and Formula One Management.