Tier Watch. This link connects to daily tier changes at OTC. The complete list for today May 5 is given here. Note that all Grey Market uptiers involve foreign-based firms; this is not unusual in their stepwise course of listing. Some of the biggest foreign firms are crosslisted on the OTC as non-reporters. The incidence of a domestic firm on Grey Sheets uptiering after suspension is the rarest of rare events.

http://www.otcmarkets.com/market-activity/otc-tier-changes