Bitcoin’s move from around $75,000 on September 16 to above $87,000 on September 21 was not caused by one piece of news. It was a chain reaction.

The Federal Reserve event came first. BTC initially remained trapped around the $75K–$77K area rather than immediately exploding higher. The market was digesting the Fed decision and repositioning.

Then came Friday, September 18. BTC broke sharply higher, reaching $81,331, while U.S. spot Bitcoin ETFs recorded approximately $433 million of net inflows. Fidelity’s FBTC alone received about $310.7 million, while BlackRock’s IBIT received about $108.4 million.

That move changed the market structure.

BTC entered the weekend holding above $80,000. Instead of giving back Friday’s gains, it consolidated around $80K–$82K.

Then Monday arrived.

Bitcoin broke through the $82,000 area and accelerated toward $87,364.

The key fuel was leverage.

As BTC moved higher, heavily leveraged shorts began getting liquidated. Reports showed hundreds of millions of dollars of short positions being forcibly closed. Because closing a short requires buying BTC, those liquidations created additional upward pressure.

Then came another extraordinary number: U.S. spot Bitcoin ETFs received $998.95 million on Monday.

BlackRock IBIT: $381.4M

ARKB: $289.1M

Fidelity FBTC: $238.8M

That meant genuine spot demand was arriving at the same time as forced buying from liquidated shorts.

This produced the classic crypto feedback loop:

BTC rises → shorts liquidate → forced buying → BTC rises further → more shorts liquidate.

That is why Monday’s move was so violent.

The important lesson is that the Fed announcement itself was not the entire catalyst. The Fed created the initial volatility and uncertainty, but the major expansion came later through a combination of ETF demand + technical breakout + short squeeze + improving risk appetite.

Now BTC is around $83,559.

The key areas are clear:

$87.3K–$87.4K: September 21 peak and major resistance.

$85K–$86K: important post-breakout zone.

$83K–$84K: current decision area.

~$82.2K: important ETF-cost-basis reference and major structural level.

$80K–$81.2K: previous breakout/consolidation zone.

$75K–$77K: September 16–17 base.

The next phase will depend heavily on whether BTC can hold the $82K–$84K region while ETF demand remains strong.

There is also a new macro complication: U.S. Treasury yields have risen sharply, with the 30-year yield reaching around 5.62% on September 29 and the 10-year around 5.29%. Higher yields can put pressure on non-interest-bearing risk assets such as Bitcoin.

So the September explosion was not simply “Bitcoin reacted to the Fed.”

It was a multi-stage repricing that turned into a leveraged short squeeze, with nearly $1 billion of ETF demand arriving on the same day.