Myth: rising open interest into a Bitcoin dip is bullish.

[Current events - Fed week, BTC perp]

Start with the numbers. A 0.1 BTC long on MEXC's BTC_USDT perpetual at the 4:20 PM ET fair price of 80,720.0 is 1,000 contracts (0.0001 BTC each), 8,072 USDT of notional. At 100x the rough isolated liquidation is 80,720 x (1 - 1/100) = 79,912.8. Today's 24h low on the same contract was 79,468.3. That position would not have survived the morning.

The myth is that rising open interest in a falling market means buyers are stepping in, so the dip is safe. Every perp contract has a long and a short, so OI cannot be one-sided. What CoinDesk's Tuesday derivatives read did show: BTC fell about 1.1% over 24h while BTC open interest rose about 1%, futures volume climbed 18% to 152B USD, liquidations fell 13% to 133M USD, and funding stayed positive. In plain terms, new positions opened into the dip and longs are still paying to hold them. That happened as the Fed's two-day meeting began, with a decision due Wednesday and FedWatch odds near 90% for no change. Spot BTC ETFs also took in 110M USD on Monday after two days of outflows, SoSoValue data showed. ETH and SOL showed the same OI-up pattern, while XRP rose on Ripple's trust bank approval and ZEC added 0.5%.

The image is MEXC's live BTCUSDT perpetual page at about 4:20 PM ET: last 80,718.4, index 80,759.3, fair price 80,720.0, funding +0.0100% with the 8:00 PM ET countdown, 24h high 80,796.6, low 79,468.3, 24h volume 27.137K BTC, turnover 2.174B and open interest 4.621B. The 24h change had recovered to +0.23% by then.

The fact is that fresh OI near the current price is fresh liquidation fuel. MEXC's own figures make the distance concrete. Fair price to the 24h low is 1,251.7, about 1.55%, so anything above roughly 64x on a long opened now would be liquidated by a repeat of today's low. MEXC lists 500x on this contract with a 0.1% maintenance rate. At 500x the rough liquidation, with that maintenance margin included, is about 80,639.28 for a long and about 80,800.72 for a short. That is a 0.1% band, and the short side sits just 4.12 above today's 80,796.6 high. MEXC liquidates against the fair price, not the last trade. Fair was 80,720.0 against an index of 80,759.3, so the perp traded slightly under spot.

Funding adds a smaller, steady cost. At 0.0100% the 0.1 BTC long pays about 0.81 USDT per settlement. 8:00 PM, 4:00 AM and 12:00 PM ET all land before Wednesday afternoon. Round-trip taker fees at 0.02% each way are about 3.23 USDT, maker 0. Neither cost is the real risk. The real risk is leverage that does not fit inside a range Bitcoin already traded today.

So the question for anyone trading MEXC futures through the decision: do you size off the leverage slider, or off the distance to the 24h low and high?

Common mistakes

• Reading rising open interest as buyers winning. Every open contract has a long and a short.
• Ignoring funding. Positive funding with rising open interest in a dip suggests leveraged longs are adding.
• Using very high leverage because it's offered. Liquidation can sit inside a normal daily swing.
• Watching last price while liquidation uses fair price.

FAQ

What does rising OI into a dip tell me? More positions are open, often leveraged dip buyers, which can fuel a flush if price keeps falling.

Why does fair price matter? MEXC uses it for liquidation, so short spikes in last price don't trigger it alone.

What should I do before the Fed decision? Size from your stop, lower leverage and check your liquidation price.

A simple routine

Before entering, write down the current funding sign, whether open interest is rising or falling, and your liquidation price. If all three point to a crowded side and you're on it, cut size first.