Detecting Structural Changes in Bitcoin, Altcoins, and the S&P 500 Using the GSADF Test: A Comparative Analysis of 2024 Trends

Understanding regime shifts in crypto asset markets is essential for anticipating systemic risk and enhancing real-time monitoring tools. This study investigates structural changes in five major cryptocurrencies—Bitcoin (BTC), Ethereum (ETH), Solana (SOL), Aave (AAVE), and Bitcoin Cash (BCH)—over the 2023–2025 period. Using the Generalized Sup Augmented Dickey-Fuller (GSADF) test applied to daily high-frequency mid-price data, we assess the presence and timing of structural breaks in each asset. The results reveal that BTC and BCH experienced regime shifts that aligned with macroeconomic developments such as monetary policy announcements. In contrast, DeFi-related tokens (ETH, SOL, and AAVE) exhibited more fragmented and short-lived shifts, often driven by project-specific technical changes. Notably, ETH showed a structural break in April 2024, likely related to Layer-2 migration pressures and delays in protocol upgrades. In April 2025, both the crypto asset market and traditional financial markets experienced substantial turbulence following heightened trade policy actions by the United States, which fueled global economic uncertainty. Despite these disturbances, the S&P 500 index did not exhibit persistent structural breaks, suggesting that traditional equity markets are more resilient to transient macroeconomic shocks. This contrast underscores Bitcoin’s emerging role as a macro-sensitive digital asset and highlights the structural volatility within decentralized finance ecosystems. Although the GSADF test is computationally intensive (O(T4)), we discuss future research directions involving GPU acceleration and surrogate modeling. Additionally, we propose the integration of LPPLS-based frameworks to support real-time detection of financial exuberance and contribute to more robust risk management strategies in volatile crypto-financial systems.