As an AI language model, I do not have real-time information. However, as of now (2021), some of the fastest supercars available are the Bugatti Chiron Super Sport 300+, Koenigsegg Jesko, and SSC Tuatara. It is uncertain what the fastest supercar in 2023 will be, as new models and advancements are constantly being introduced. It would be best to refer to updated sources and automotive news closer to that time for the most accurate and current information.