September Slump? New Research Shows Seasonal Market Myths Don’t Hold Up

For a long time, people have thought of September as the “worst month” for markets, with traders often preparing themselves for seasonal drops as if they were guaranteed.

However, new research shows that these calendar-driven narratives are more superstition than signal, and holding on to them could even cost investors money.

The Myth of September Weakness

On September 3, investment services provider Market Radar sought to dismantle the popular “Sell in September” narrative. In a detailed post, the platform’s analysts highlighted that most seasonality charts rely on averages, which are easily skewed by outliers such as crashes or extraordinary rallies.

However, when measured by medians, which, according to Market Radar, is a better gauge of typical returns, the picture changes dramatically. September’s median return, for example, is only –0.3%, far from the narrative of a guaranteed slump.

The firm stressed that even with median-based analysis, no month shows consistent predictive value. Win rates across all months hover near a coin flip, with December reaching only ~59% and November dropping to ~41%.

“If seasonality worked, you’d expect win rates well above 50%. Instead, most months are indistinguishable from random guessing,” the post noted.

The research also applied statistical significance tests, which found that every month sits above the conventional cutoff for randomness (p = 0.05). In other words, the apparent seasonal patterns could easily be explained by noise rather than repeatable signals. So, what looks like “September weakness” is really just part of the broader distribution of outcomes.

Even more, Market Radar argued that smooth seasonal charts simply reflect the market’s natural upward bias over time. Investors often interpret these tidy lines as hidden rhythms, but in reality, they only mirror the fact that equities rise more often than they fall.

“Markets don’t move because of calendar rhymes,” the firm concluded. “They move on growth, inflation, and liquidity. Seasonality is noise. Macro is the signal.”

This skepticism comes as many analysts still warn about Bitcoin’s historical struggles in September. As previously reported by CryptoPotato, the asset has delivered negative returns in eight of the past twelve years.

Similarly, another report shows that BTC’s monthly high or low tends to occur within the first 12 days, with 2017 and 2021 seeing more than 7% pullbacks during bullish cycles. While such data feeds into the “Septembear” label, critics argue these numbers lack predictive weight.

Bitcoin Price Action and What Lies Ahead

In the last 24 hours, BTC fluctuated between $108,538 and $111,640, probably showing that participants are being cautious as the month starts. It finally settled at $110,500, a slight 0.4% uptick in its price from the same time yesterday.

While the asset has had a hard time getting back to its mid-August peak above $124,000, falling nearly 11% from that all-time high, its performance over longer horizons is much more encouraging.

The number one cryptocurrency has gained nearly 88% year-on-year, with its dominance still strong compared to altcoins, showing it as a relatively safe haven during times of high volatility. Analysts note that miner-driven sell pressure in August, exacerbated by soaring electricity costs, has historically weighed on prices, but this effect tends to fade heading into autumn.