Altcoin gains have slowed noticeably in recent weeks, data showed.

CoinPost, a blockchain media outlet, reported on Sunday that on-chain analyst Darkfost assessed that an altcoin bull run from late August to early October is losing strength.

Darkfost said the altcoin season is "cooling rapidly". He based the assessment on the share of Binance-listed altcoins trading above their 200-day moving average. The 200-day line is a key gauge of medium- to long-term trends, and the analysis used CryptoQuant data.

For about 2 months after late August, the number of tokens in a bullish trend rose quickly. The share of tokens below the 200-day moving average fell from 81 percent to under 10 percent. That meant more than 9 out of 10 Binance-listed altcoins moved into an uptrend.

Funds moved in the same direction. Darkfost explained that more than $814 billion flowed into the overall altcoin market during the period. He said the combination of price moves and inflows widened gains across altcoins.

But sentiment has shifted recently. The share of tokens falling back below the 200-day moving average rose to 48.4 percent. The share trading above the 200-day line shrank to around 52 percent from above 90 percent. That means the number of tokens maintaining an uptrend has fallen to about half.

Fund flows have also turned weak. More than $134 billion has left the altcoin market over the past 15 days. Darkfost said the outflows are likely driven largely by short-term profit-taking.

Darkfost also pointed to the altcoin market's sensitivity to shifts in investor sentiment. He said market direction can change easily over a short period. In such conditions, he mentioned that the point at which attention and returns have fallen the most could be a time to consider rebalancing allocations. He added that in the past, periods in which market heat and performance cooled together served as reference points for later strategy adjustments.

The analysis shows that the altcoin market is not just undergoing a simple price correction but is also showing signs of slowing in both trend indicators and fund flows. In the short term, the next points to watch are whether gains broaden again and whether outflows persist, and whether the share of tokens remaining above the 200-day moving average declines further.