Open offer size rules require minimum public acquisition and limits to prevent exceeding maximum non-public shareholding, with scale-down option. Regulation 7 mandates minimum open offer size requirements and adjustments tied to changes in a target's share capital, requires offers to secure an additional increment of voting rights subject to the cap imposed by maximum non-public shareholding, allows a time-limited increase in offer size in response to a competing offer, and treats such increases as offers under the principal acquisition provision. If open offer acceptances would breach maximum non-public shareholding, the acquirer must reduce non-public shareholding to the permissible level; alternatively, an acquirer who has declared intent to retain listing may proportionately scale down the underlying acquisition/subscription subject to eligibility conditions and timing rules.