#Gate广场五月交易分享 What is the reason behind Bitcoin's seasonal pattern in May?

BTC's weaker performance in May is not a coincidence; multiple intertwined factors are at play:
1 Traditional financial "Sell in May" effect transmission
Wall Street has long propagated the saying "Sell in May and Go Away"—from May to October, the average return of U.S. stocks is significantly lower than from November to April of the following year. The reason lies in decreased institutional trading activity during summer, shrinking trading volumes, and lower risk appetite.
Although BTC is an independent asset, a large amount of institutional and ETF fund flows are highly correlated with the US stock market rhythm. When the traditional market enters its "off-season" mode, incremental funds slow down, and BTC also comes under pressure.
2 Tax and fiscal year cycle
The US individual and corporate tax deadline is April 15. Many investors sell assets before April to pay taxes, leaving May in a "post-cash recovery but not yet redeployed" vacuum. Meanwhile, many funds use the calendar year as their fiscal year. After completing their allocations in the first half of the year (especially Q1), they enter a wait-and-see and rebalancing phase in Q2, reducing new investments.
3 The "post-halving low" cycle of halving
BTC halves every four years. Historically, halvings occur between March and May (2012 in November, 2016 in July, 2020 in May, 2024 in April). The 1–3 months after halving are often a period of stagnation—miners' income drops sharply, leading some miners to sell off to recoup funds, the market waits for supply-demand rebalancing, and narratives have not yet shifted to "halving benefits realized." After the 2020 halving, BTC consolidated for nearly two months in May–June before rallying; similarly, after the 2024 halving, May experienced sideways movement. This "excitement → digestion → restart" rhythm coincides with May–June.
4 Uncertainty in macro policy windows
May is typically a period of frequent Federal Reserve meetings, inflation data releases, and employment reports. In May 2025, additional uncertainties such as tariff negotiations and fluctuating rate cut expectations are layered in. During the market's wait for clearer policy signals, leverage is reduced, and exposure is decreased, with BTC, as a highly volatile asset, leading the decline.
5 Self-fulfilling seasonal narrative
When the "Sell in May" phrase is repeatedly mentioned, traders tend to reduce their positions or set more conservative stop-losses in advance. This behavior itself suppresses prices and trading volume—turning the narrative into a self-fulfilling prophecy. Data from CoinGlass shows that in recent years, BTC's performance in May has generally been weak, and if May declines, June often continues to weaken (this has happened in 4 of the past 5 years), creating a negative feedback loop.
6 "High mean but low median" in Q2 data
Over the past 12 years, BTC's average Q2 (April–June) return has been 26%, but the median is only 7.5%, indicating that a few explosive rallies (such as +52% in May 2019) skew the average upward, while most years are flat or even weak in Q2. Q3 (July–September) sees an even lower average gain of 6%, with a slightly negative median—indicating a stable pattern of "post-Q2 peak, Q3 consolidation and weakness." The truly strong window is in Q4, with an average increase of 85.4% and a median of 52.3%.

In simple terms, the weaker performance in May results from the combined effects of institutional fund flow slowdown, tax cycle draining, post-halving digestion, macro uncertainty, and self-reinforcing seasonal narratives. Of course, there are exceptions (such as a 52% surge in May 2019), but statistically, the "weak May" pattern has structural support and is not purely coincidental.