The cryptocurrency REEF has experienced a significant drop in value for several reasons:

Delisting from Binance: In August 2024, Binance decided to delist REEF from most of its trading products, including the REEF/USDT and REEF/TRY pairs. Delisting from such a major exchange greatly impacted investor confidence and liquidity. Although perpetual contracts for REEF remained available, the news led to a sell-off among holders​
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Security Breaches on Exchanges: In September 2024, one of the exchanges supporting REEF experienced a hot wallet breach, raising concerns about the safety of assets, which likely contributed to the price decline​
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Despite these setbacks, the REEF project continues to develop its ecosystem, including products like ReefSwap, which could potentially stabilize the price in the future.