There are two factors for daily cost/revenues associated with short selling of stocks and bonds at IBKR:
For more information see:
Pursuant to the Treasury Laws Amendment (Design and Distribution Obligations and Product Intervention Powers) Act 2019, Interactive Brokers Australia Pty. Ltd. has prepared the following target market determinations relating to certain financial products for which it is deemed to be the issuer. Our Target Market Determinations are located here: Target Market Determinations.
Product Disclosure Statements are also available for each of these products. You should carefully consider these Disclosures in deciding whether to acquire, or to continue to hold, the relevant financial product.