In crypto, whale wallets are visible on-chain and tracked obsessively. In stocks the equivalent is a large fund or insider whose 13F filings or Form 4 sales are watched.
A whale moving coins to an exchange is treated as a sell warning; a whale accumulating is treated as bullish. Both readings are often wrong.
Example: a wallet holding 50,000 BTC transfers 5,000 to an exchange. That is roughly $300 million at $60,000, enough to move a thin market if sold at once.
Related: on-chain, wallet, liquidity, market-cap