Pool A/B Comparison
Pool A/B data comparison for 596 IPO stocks
This page aggregates Pool A and Pool B data from all HK IPOs with publicly available allotment details, presenting the differences through four interactive charts. Whether you're new to IPO subscription or an experienced investor, understanding how Pool A/B works can help you make more informed subscription decisions.
Under HKEX Listing Rules, the Public Offer tranche is split into Pool A and Pool B based on subscription amount:
Pool A: Subscription orders of HK$5 million or below. Pool A typically represents retail investors and small-to-medium subscriptions.
Pool B: Subscription orders exceeding HK$5 million. Pool B represents high-net-worth individuals, professional investors, and institutional investors.
HK$5 million is the threshold separating Pool A from Pool B. This threshold was formalized by HKEX upon the launch of the FINI platform. Both tranches follow the same clawback mechanism, but due to the significant difference in subscription size, the allotment rates and capital efficiency between the two groups often differ materially.
A-Tail: The highest subscription tier within Pool A, i.e., the tier closest to the HK$5M threshold.
B-Head: The lowest subscription tier within Pool B, i.e., the tier just crossing the HK$5M threshold.
A-Tail and B-Head are closest in subscription amount and form the core comparison pair for allotment rates and capital efficiency. The first two charts on this page are dedicated to comparing these two tiers.
| Term | Chinese | Definition |
|---|---|---|
| Pool A | 甲组 | Subscription tiers with amount ≤ HK$5M, representing the lower end of the public offer |
| Pool B | 乙组 | Subscription tiers with amount > HK$5M, representing the upper end of the public offer |
| A-Tail | 甲尾 | The highest subscription tier within Pool A, closest to the HK$5M threshold |
| B-Head | 乙头 | The lowest subscription tier within Pool B, just above the HK$5M threshold |
| Expected Allotment Lots | 期望中签手数 | The expected number of allotted lots at a given subscription tier, calculated as: Allotment Ratio × Subscribed Shares / Lot Size |
| Frozen Capital | 冻结资金 | Funds temporarily locked during IPO subscription. Freeze duration is based on the expected settlement dates per the prospectus. This is an implicit cost of IPO subscription |
| Capital Efficiency | 资金效率 | Expected allotment lots per HK$10,000 of frozen capital (lots/10K HKD). A higher value means more lots per unit of capital committed |
| Oversubscription Ratio | 超额认购倍数 | Total public offer subscription amount / initial offering size, reflecting market demand for the IPO |
| Allotment Ratio | 配发比率 | The percentage of subscribed shares actually allotted at each tier, determined by the clawback mechanism and allotment algorithm |
Chart 1: A-Tail vs B-Head — Expected Allotment Lots Ratio
Compares expected allotment lots between A-Tail and B-Head for each IPO. The Y-axis shows the deviation multiple: B-Head prevails means B-Head gets more lots than A-Tail (ratio > 1); A-Tail prevails means A-Tail gets more lots (ratio < 1, shown as reciprocal). The dashed line at y=1 represents parity. Use the zoom slider to explore earlier IPOs.
Chart 2: A-Tail vs B-Head — Capital Efficiency Ratio
Building on expected lots, this chart incorporates frozen capital cost. Capital efficiency = expected lots / frozen capital (per 10K HKD). For the same allotment outcome, more frozen capital or longer freeze periods reduce efficiency. This chart helps investors balance allotment rates against the opportunity cost of locked funds.
Chart 3: Pool A vs B Applicant Distribution (Time Series)
Diverging bar chart showing applicant counts per IPO. Pool A (blue) extends upward, Pool B (red) extends downward. Time trends reveal: both groups increase during market booms; Pool A consistently outnumbers Pool B (larger retail base); larger IPOs see higher Pool B participation.
Chart 4: Pool A vs B Fund Distribution (Time Series)
Same mirror structure as Chart 3, but showing total subscription funds. Note that Pool B funds often dwarf Pool A (as Pool B consists of high-net-worth/institutional investors placing much larger orders), visually demonstrating the structural feature of public offers where "a few large orders account for the majority of funds."
Important: The A-Tail vs B-Head comparison reflects the difference between tiers just below and just above the HK$5M threshold. Since different IPOs may have different tier structures, the specific subscription amounts for A-Tail and B-Head can vary by IPO. The data on this page is for educational reference only and does not constitute investment advice.
This page aggregates Pool A and Pool B data for 596 HK IPOs with disclosed allocation details, comparing the two groups on applicant count, capital size, allocation efficiency and first-day return, plus an explainer on the A/B rules. Data is computed from share registrar allotment announcements.
