"Experts said it was likely that the NSA or FBI had approached other Internet companies with the same demand, since they evidently did not know what email accounts were being used by the target. The NSA usually makes requests for domestic surveillance through the FBI, so it is hard to know which agency is seeking the information.
Reuters was unable to confirm whether the 2015 demand went to other companies, or if any complied.
Alphabet Inc's Google and Microsoft Corp, two major U.S. email service providers, did not respond to requests for comment."
It's not a hard question to answer. You either are or are not searching all emails in realtime at the behest of the NSA.