In a
hostile takeover, the act of an acquiring firm or, more rarely, an individual
investor buying a substantial amount of a
target firm's stock at the beginning of the
trading day. One perpetrates a dawn raid to take the target firm by surprise; by not making a formal
offer to
buy the company before the dawn raid, the acquiring firm does not give the target firm the chance to enact an
antitakeover measure that would increase the
cost of the takeover. Regulations allow an acquiring firm to buy only 15% of the target firm in a dawn raid; many acquiring firms thus make formal offers after they have a significant stake in the target firm.