I have been in the US for six years. First O-1B expired on Feb15, sent in application for the 2nd O-1B already in December. The itinerary wasn't sufficient, response due by April 26th, ready to send in the completed itinerary plus additional letters of intended employment. My household is in New York. I am still here. Am I illegal now? Is there a grace period?
As long as you had filed your extension application before expiration of the current status, you are not illegal as long as the case is pending. You are in authorized period of stay.