What is when-issued trading? How are issues trading when-issued handled in the CRSP stock database?

Securities trade on a when-issued basis when officially they have yet to be issued, but they trade as if they have been. These transactions are formally settled after the securities have been issued.

INCLUDED IN THE SUBSCRIBER VERSION OF THE STOCK DATABASE

"Reorganization" - All of the shares of an established security are trading when-issued due to some type of restructuring

EXCLUDED FROM THE SUBSCRIBER VERSION OF THE STOCK DATABASE

"Leading prices" - All of the shares of a security are trading when-issued at the start of its trading history

"Additional" - A security issues more shares that trade when-issued, during the same time that the established shares of the security continue to trade regular-way

"Ex-distribution" - A portion of a security's shares trade when-issued and without entitlement to a particular distribution, during the same time that the rest of its shares trade regular way, with the entitlement to the distribution