Editor’s note: This is general educational information about the circumstances in which trading in a Nairobi-listed security stops during a session, drawn from the exchange’s trading rules and the applicable regulations listed at the end. It is not investment advice and does not describe any particular security.
Analysis: the automatic halt is the one that costs money
Most commentary treats halts as circuit breakers. In Nairobi the circuit breaker is the least likely of them to appear. The index trigger requires the 20 share Index to move more than 5% within a session, and that index is an equal-weighed geometric mean of twenty stocks, a construction that damps the effect of any single large move. A market-wide fall big enough to trip it would have to be broad, not concentrated.
The frequent halt is the automatic one in rule 6.10.4, and its design has a sharp edge. It is triggered by the arrival of an announcement rather than by any price movement, it runs for the rest of the session rather than for a fixed short period, and it purges pending orders rather than freezing them. A resting limit order placed before an announcement does not wait out the halt. It is cancelled, and the holder must re-enter it in the next session, when the 10% band does not apply to that security at all.
That pairing is the part worth internalising. The rule removes the price limit precisely for the session in which the market is repricing on new information, which is coherent as market design and unforgiving for anyone relying on a standing order. It also gives a practical reading of the tape: a security that stops for the balance of a session, with orders gone, most likely received an announcement, while a security stopped briefly and resumed within the same session is more likely under a discretionary halt for unusual price or volume movement or pending a clarification. The public announcement obligation only bites for halts extending beyond one session, so the shorter events are visible in the trading platform’s own announcements rather than in a press release.
What the documents say
A Nairobi equity can stop trading in the middle of a session for reasons that have nothing to do with anything going wrong. The NSE Equity Trading Rules, amended July 2025, distinguish a market halt from a security halt, attach different triggers to each, and set out what happens to orders sitting in the book when either lands. The rules also make one halt automatic in a way that surprises readers: an issuer announcement received during a session stops that security for the rest of the day.
Two kinds of halt, and who can call them
The rules define a trading halt as a market halt or a security halt, and a security halt as the temporary stopping of trading in a particular security. Trading of listed equity securities runs in sessions commencing at 9.00 a.m. and closing at 3.00 p.m. each day, timed by the clock displayed through the automated trading system.
Under rule 9.1 the Chief Executive may, on prior consultation with the Authority, vary the duration of trading or suspend trading for one or more trading sessions or any part of a session, with any such halt reported immediately to the Trading and Technology Committee. Rule 9.2 provides that a trading halt may be imposed by the Exchange following approval by the Authority for a period during a session or extended beyond one session. Trading participants are told through the announcement system of the trading platform, and the Exchange makes a public announcement only where a halt extends beyond one trading session.
A market halt can occur in three circumstances. A technical failure of the automated trading system. A fall in the 20 share Index of more than 5% at the opening session compared with its closing value, or during the continuous session compared with its opening value, in which case the halt will not be for more than 30 minutes. Or where in the opinion of the Chief Executive circumstances exist or are about to occur that could result in other than transparent, fair and orderly trading of listed securities, unless the Authority approves otherwise.
A security halt may be imposed on one or more securities at the request of the Authority, or by the Exchange before obtaining a clarification from a company on a report about it that has been brought to the Exchange’s attention, or when there are unusual market movements in the price or volume of a security, or on the Chief Executive’s opinion about orderly trading in that specific security.
What happens to the order book
The consequences are not symmetrical, and rule 6.10 is the part most likely to affect an ordinary order. An issuer must release announcements as soon as possible and not later than twenty-four hours, in accordance with Chapter 10 of the NSE Listing Manual. On receipt of material information and corporate action announcements the Exchange sends the entire text, not an abridged version, to trading participants. If an announcement is received from an issuer of a listed equity security during a trading session, the Exchange shall impose a security halt on that security for the rest of the trading session. All pending orders on that security are then purged. The halt is lifted during the next trading session, and the daily allowable price movement limits do not apply to that security for that entire session.
In a discretionary halt the treatment of the book depends on suspicion. Trading participants are prohibited from effecting transactions in a security under an announced halt. Where the Exchange has reasonable grounds to suspect collusion or market manipulation it may delete the orders in the order book at the time of the halt. Where orders are not deleted, participants may withdraw their own orders during the halt, and no other changes to the book are permitted.
The price limits that sit underneath
Halts interact with a daily price cap. Rule 5.10 provides that the daily price movement for an equity security in a single trading session shall not be more than 10% of the equity average price determined during the previous session, and 5% for a security listed on the recovery board. Where no trades were concluded in the previous session, the 10% is measured against the reference price on the last day the security traded, and no market order is accepted by the trading system in that case.
The exemptions matter as much as the rule. The limit does not apply where the issuer, exchange traded fund or real estate investment trust announces its financial results or material information, in the first session of trading ex entitlement, where the security has not traded for over three calendar months, or to block trade transactions. Offshore, commodity and certain domestic exchange traded funds may also be exempted, with offshore fund limits based on those imposed in their home jurisdiction and on currency movements.
Suspension is a different instrument
A halt and a suspension are separate legal events. Regulation 72 of the Capital Markets (Securities) (Public Offers, Listings and Disclosures) Regulations, 2023 lets a securities exchange, with the approval of the Authority, grant a trading halt or suspend trading in an issuer’s listed securities at any time, and allows a halt or suspension at the issuer’s request or the Authority’s direction, though the exchange is not obliged to honour an issuer’s request. A trading halt shall not exceed one trading session at any one time and may, with the Authority’s approval, be changed to a suspension at any time. At the Authority’s written direction the exchange must halt or suspend trading in all securities or close the market before the normal close of the session.
Regulation 73 bars suspension or delisting without the Authority’s prior written approval, and lists the grounds on which the Authority may require suspension: a decision made or imminent to place the issuer under statutory management, receivership, liquidation or voluntary winding up; a significant restructuring involving the listed securities, including during an acquisition, merger or takeover; a directors’ recommendation approved by special resolution at which at least seventy-five per cent of holders are represented without objection from at least ten per cent of holders; or material default of continuing listing obligations. A suspension runs for such period as the Authority approves, and during it the issuer must continue to comply with its continuing listing obligations. Behind both instruments, section 21A of the Capital Markets Act lets an approved exchange make rules for its activities, products, systems and fees, section 21B requires them to be submitted to the Authority not less than thirty days before introduction, and section 21C lets the Authority abrogate them.
