Detection of bubble formation in cryptocurrency prices: Examples of Bi̇tcoin, Ethereum, MANA, Ripple, Tether, AVAX, BNB, and Dogecoi̇n

Speculative bubbles have been always observed throughout the history. Recently, cryptocurrencies, especially Bitcoin, have gained significant attention. Although cryptocurrencies were initially introduced as decentralized, transparent, and reliable payment methods, they are now predominantly used as investment instruments. Therefore, in this study the cryptocurrencies with the highest trading volumes in 2022 were examined within the framework of "bubble", aiming to provide investors a different perspective. The price movements of the cryptocurrencies covered in the study from 2014 to 2023 were analyzed using the GSADF test, and the existence of bubbles was proven for most of the cryptocurrencies. It is also highlighted that since governments have not yet prepared a legal framework for cryptocurrencies, not only speculation but also fraud is frequently met in cryptocurrency markets.