Bitcoin trading volume is falling fast. That rarely ends smoothly.

Even as calls for bitcoin BTC$77,652.75 to rally further are growing, participation in the spot market is cooling, leaving the door open for erratic price action.

Trading volume, the dollar value of BTC changing hands in a day, has recently dropped to less than $8 billion, according to Glassnode. That's the lowest since October 2023, when bitcoin was less than $40,000. Volume has been declining since hitting highs above $25 billion in early February.

"Such low volume environments often coincide with reduced market depth and heightened sensitivity to flow shifts," Glassnode said.

Market depth, typically measured by looking at buy and sell orders within 2% of the current price, is widely used to assess liquidity, or the ability of the market to absorb large orders at stable prices.

When market depth shrinks, it means a few large orders can move prices significantly. In other words, the declining volume might end up boosting market volatility, though options traders do not seem to be considering that scenario for now.

Volmex's BVIV index, which measures BTC's expected 30-day price swings, has dropped to three-month lows below an annualized 42%. Clearly, traders are positioned for calm, not turmoil.

It's notable, especially because the Fed sets interest rates later today. Nobody expects a change; attention will focus on what the policy statement has to say about energy-market disruptions and rising prices at gas stations. A hawkish statement, expressing alarm over growth and inflation risks, could mean a prolonged pause in rate reductions, and even possible rate increases, capping gains in risk assets.

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"Bitcoin is sitting around 77k and trading like a market that does not want to commit ahead of the Fed. The tape is calm on the surface, but it is not relaxed. Positioning is cautious, liquidity is thinner, and the next impulse is more likely to come from macro than anything crypto-native," Marex analysts said in a morning note.

"The big macro curveball is energy politics. If energy becomes less predictable, risk assets stay headline-sensitive," they said, noting the UAE's Tuesday decision to leave OPEC and OPEC+.

BTC recently changed hands near $77,800, up over 1% in 24 hours, with ether (ETH), solana (SOL), and XRP adding similar amounts. The CoinDesk Memecoin Index is leading the market higher, with 3% gains, followed by the Computing Select Index, which is up 2.7%.

In traditional markets, the Dollar Index, which is inversely related to bitcoin's price, continues to stay below 100, lacking bullish momentum. However, yields on the 10- and two-year U.S. Treasury notes continue to rise, albeit slowly. Stay alert!