From Longman Business Dictionary
oversubscribedo·ver·sub·scribed /ˌəʊvəsəbˈskraɪbd◂ˌoʊvər-/ adjectiveadjFINANCE an oversubscribed SECURITIES ISSUE has people asking for more shares etc than are available. If this happens, each buyer receives fewer shares than they asked for, or there is a BALLOT to decide who will receive themThe bonds were oversubscribed, and there will be no unsold balance remaining, the underwriter said.
—oversubscription noun [uncountableU]Analysts expect them to receive only about 2.5% of the shares they ordered because of massive oversubscription.