Space within an IMS database can be managed during loading or updating of the database. After an IMS database is loaded, a space management program can assume control from the IMS program for a period of time. During this period of time, the space management program obtains memory addresses of IMS control blocks built by the IMS program and further obtains information about the IMS database. When the IMS program attempts to insert data into the IMS database, either during loading or updating of the database, the space management program reassumes control from the IMS program. The space management program selects a storage location for the data to be stored, and modifies the IMS control blocks to indicate the storage location selected. The space management program may also insert the data into the storage locations selected. Control is then passed back to the IMS program. If segments are to be inserted into the IMS database, and such segments are to be split, then the space management program selects two storage locations for the components of the split segment to be stored. The storage locations selected by the space management program are selected based on IMS database user preferences.