The Calendar Trade: PISCES and the Limits of Scheduled Private-Share Liquidity

The Private Intermittent Securities and Capital Exchange System has always been sold as a modest idea with a large ambition. It would give private companies a regulated venue for secondary trading in scheduled windows, letting early investors and employees realise value without forcing the company into a full listing. In 2026, as the first cohort of PISCES venues and issuers moves from design to operation, the modest part is visible. The large ambition is still unproven.

The case for PISCES rests on a gap in London's capital ladder. A company can raise private capital, and eventually it can list. Between those points, secondary trading is episodic, negotiated and opaque. PISCES promises a middle rung: more structure than a private secondary, less burden than an IPO. That is a sensible objective. But a venue can schedule a trading window; it cannot schedule a buyer. The difference matters.

A Window Is Not a Market

Intermittent trading is often described as a liquidity solution. It is better understood as a liquidity format. The format has advantages: issuers can control the cadence of trading, disclosure can be tailored to the venue's rules, and investors know when exits may be possible. For a private company, that is preferable to an open-ended market in which the register can churn unpredictably.

Yet liquidity is not merely the permission to trade. It is the presence of enough independent buyers and sellers, with enough information, to establish a price that both sides accept. A scheduled window can concentrate that process, but it can also concentrate its weaknesses. If most holders want to sell in the same window and few want to buy, the result is not a market. It is an auction with a known imbalance. The discount that emerges may be real, but it may also reflect the calendar rather than the company.

This is the first test for PISCES. The regime's design rightly avoids pretending that private shares can be made continuously liquid by regulation. The risk is that intermittent trading becomes a formalised exit event, priced at a predictable discount, rather than a step towards broader ownership.

The First Cohort's Instinct for Caution

The first cohort of venues and issuers has been cautious, and that is understandable. Venue operators have an incentive to curate. Issuers have an incentive to control who joins the register. Investors have an incentive to avoid windows that look thin. The result is a market that may launch with more governance than volume.

Caution is not a defect in a new regime. PISCES is dealing with private companies whose disclosure, shareholder agreements and valuation practices were not built for a trading venue. A slow start is preferable to a rushed one. But cautious design has a cost. If each venue sets its own eligibility, disclosure and settlement conventions, the market fragments before it scales. If issuers can effectively select the buyers, liquidity becomes permissioned rather than priced. That may suit founders. It does not necessarily suit the institutions whose capital the regime needs.

The UK has seen this pattern before in less formal private secondary markets: plenty of introductions, limited price discovery, and a reliance on bilateral negotiation. PISCES can improve the plumbing. It cannot remove the underlying negotiation unless venues attract committed market-makers and a broad enough pool of participants.

The Ladder and the Destination

The policy hope is that PISCES strengthens London's growth-capital ladder. A company that can offer periodic liquidity may find it easier to retain employees with share schemes, attract later-stage investors and delay a listing until it is ready. On that view, PISCES is a staging post.

There is a less comfortable possibility. If private companies can obtain enough liquidity without listing, some will choose to remain private for longer. That is rational for them. It is not obviously rational for London's public markets, which need a pipeline of issuers to replace those that are acquired or leave the register. PISCES could therefore ease the pressure on individual companies while adding to the structural pressure on the public market.

The answer is not to burden PISCES with listing expectations. It is to judge the regime on graduation. Do companies use PISCES as a bridge to AIM or the Main Market, or as a substitute for both? Do PISCES prices inform later funding rounds and valuations? Do employees and early investors obtain genuine exits, or merely a right to queue? These are more useful measures than launch announcements.

Relocating the Problem

The central risk is that PISCES relocates the liquidity problem rather than solving it. Private shares remain private shares. Their value depends on information that is not always public, on shareholder agreements that may restrict transfer, and on a buyer base that is narrower than the public market's. A regulated window does not change those fundamentals. It changes the venue, the timetable and the disclosure wrapper.

That does not make PISCES pointless. A formal window can improve price transparency, reduce the scope for ad hoc discounts and give sellers a known process. It can also impose discipline on valuations, which is useful in a market where marks can lag reality. But investors should be clear about what they are buying: an intermittent exit route, not a continuous market. The distinction should be reflected in valuations, liquidity premiums and governance terms.

What to Watch

The first year of operation should be read through a few practical indicators. The number of issuers is less important than the number of independent participants in each window. Average turnover matters less than repeat turnover. A market that depends on one seller and one buyer is not liquid, however often it meets. The spread between PISCES prints and recent private funding rounds will show whether the venue is discovering prices or ratifying them. And the flow of issuers towards public markets will show whether PISCES is a rung on the ladder or a room at the top.

For London, the prize is not a busier private market for its own sake. It is a capital ladder that allows companies to raise, grow and eventually broaden their ownership. PISCES can help if it makes that progression easier and more transparent. It will disappoint if it becomes a calendar of controlled exits, offering the appearance of liquidity while leaving the underlying market as thin as before. The calendar can organise a sale. It cannot manufacture a buyer.