How Many Confirmations Are Typically Recommended for a Large-Value Transaction and Why?

Typically, 6 confirmations are recommended for a large-value Bitcoin transaction. This number is a historical and statistical benchmark.

After 6 blocks have been mined on top of the transaction's block, the probability of a successful malicious re-org (a double-spend) is considered astronomically low, making the transaction practically irreversible. The number of required confirmations is a risk-tolerance decision, increasing with the value of the transaction.