The penalty for late filing of IRS Form 3520 can vary depending on the circumstances. As of 2021, the general penalty for a failure to timely file Form 3520 is 5% of the amount of the foreign gift or bequest per month, up to a maximum of 25% of the total value. However, if the failure to file was due to intentional disregard, the penalty can be 35% of the amount of the foreign gift or bequest per month, also capped at 25%. It is important to note that these penalties can be subject to additional interest charges on the unpaid amount.