Bitcoin’s spot supply on exchanges is tightening as the asset trades near $83,000, according to a Sept. 28 BlockBeats report citing on-chain analyst Axel Adler Jr.
Adler’s latest report said the 7-day average of net BTC outflows from exchanges climbed to 16,100 BTC per day as of Sept. 27, the strongest level since early October 2025. The shift was sharp. On Sept. 20, the 7-day average for exchange net flows still showed inflows of 7,300 BTC per day. By Sept. 22, the direction had reversed, and net outflows kept expanding afterward.
Adler said exchange net outflows should not be read as a direct proxy for new buying. Even so, they do signal that the pool of Bitcoin readily available for market trading is shrinking. That is commonly viewed as a sign of potential accumulation or transfers into long-term custody.
Derivatives positioning, however, has not produced an equally strong upside confirmation. Adler’s Bitcoin position index showed that the 30-day average advantage held by perpetual futures buyers fell from 7.6 on Aug. 27 to -1.4 on Sept. 28. The measure has stayed below the zero line since Sept. 23.
The index tracks the difference in activity between buyers and sellers in the futures market. A negative reading means bulls are not in control for now. Still, a reading of -1.4 remains close to neutral, which means the bearish side has not opened a clearly wider lead either.
The analyst said that if exchange net outflows continue and the position index moves back above zero, the contraction in Bitcoin supply would gain stronger trend confirmation. If net flows turn back to inflows while futures buying remains weak, the increase in exchange-held coins available for sale would become a short-term risk.