The amount required for authorization is 0.5% of the opening bid of the auction up to a maximum of $4,000.
For example, if an opening bid for a property is $500,000, the necessary preauthorization amount is $2,500 ($500,000 x 0.5%). If a property has an opening bid of $1,000,000, the necessary preauthorization amount would be capped at $4,000 ($1,000,000 x 0.5% > $4,000).
Remember, credit cards are ONLY CHARGED if a winning bidder is delinquent.