A retail investor with a small portfolio who wishes to purchase a small number of shares of an IPO is more likely to receive an allocation of shares when: an IPO is undersubscribed.he or she have a standing order with the underwriter to purchase shares in every IPO handled by that underwriter.he or she bids a higher amount as the offer price than do other investors.the IPO is substantially oversubscribed than when it is not.an IPO is severely underpriced.