Remember you can file below that threshold, and may be encouraged to do so in some cases. The info. from the FDIC below, while dated, specifically notes "It is recognized, however, that with respect to instances of possible terrorism, identity theft, and computer intrusions, the dollar thresholds for filing may not always be met. Financial institutions are encouraged to file nonetheless in appropriate situations involving these matters, based on the potential harm that such crimes can produce. Even when the dollar thresholds of the regulations are not met, financial institutions have the discretion to file a SAR and are protected by the safe harbor provided for in the statute."
FDIC SAR Info.