We've conducted several investigations, more than 30.
Investigations aren't always closed the moment a warning letter or a notice of violation is issued. A big part of our job is ensuring that companies remain in compliance after they've been the subject of an investigation. For instance, we have several investigations where, after we issue a warning letter, we'll do some follow-up to ensure compliance is achieved and monitor their activities, check in on their compliance programs.
I believe that, to date, we've issued about a half a dozen notices of violation. We've issued more than 10 warning letters and several other kinds of enforcement actions. Undertakings, especially, are quite helpful. We have the ability to engage in a negotiated discussion with the subject of an investigation when it wishes to voluntarily come into compliance. That's a particularly effective tool for us. We can negotiate the terms with the party involved and ensure part of that includes a robust compliance program going forward.