The "500-day rule," popularized by Pantera Capital in 2023, suggests that historically, buying Bitcoin approximately 500 days before a halving and selling approximately 500 days after has yielded significant profits in previous cycles. However, market observers believe that this pattern may no longer hold true in the current cycle due to the launch of US spot Bitcoin ETFs and the increasing influence of institutional investors.

Analysts point out that the daily inflows into spot Bitcoin ETFs (approximately $100 million to $1 billion in 2024 and 2025) have far exceeded the value of new Bitcoin produced daily by miners after the halving (approximately $35 million to $40 million). This makes institutional demand and macroeconomic conditions more influential on the market than the halving itself. Mati Greenspan, founder of Quantum Economics, and Jason Fernandes, co-founder of AdLunam, both stated that changes in the Bitcoin investor base have reduced the rule's relevance. Nevertheless, Vineet Budki, managing partner at Sigma Capital, still believes that Bitcoin's four-year cycle remains a structural anchor for market dynamics, primarily driven by miner economics.