Reservation thresholds: the maximum daily move on the BVMT
Two limits, not one
Mizen editorial team · published 02/09/2026 · checked 30/10/2026 · Translation; the French version is authoritative
The STATIC limit is measured against the reference price — yesterday's close. The DYNAMIC limit is measured against the last traded price, and is ± 2 %. A stock can therefore be reserved without reaching its static limit, simply for moving too fast.
The reservation lasts 10 minutes, then trading resumes with an auction. A day-valid limit order placed outside the thresholds is rejected — article 92 of the exchange's general regulation.
The reference price
Thresholds are set by the trading rules (Règlement de parquet) in force since 28 September 2026. They are calculated from the reference price: the last traded price of the previous session, adjusted if applicable for a corporate action. It can also be an “indicative last price”: for example the reservation threshold recorded at the previous close, a takeover bid price, or an IPO price.
Example. A Group 11 share has a reference price of 10.000 DT. Its static threshold is ±6% : it cannot trade above 10.600 DT or below 9.400 DT during the session.
The tick size is 0.01 DT for securities quoted in dinars. If, on a very low-priced security, both thresholds fall back on the reference price, the system automatically widens them by one tick.
The threshold depends on the quotation group
Every stock trades in a group, printed in the official bulletin. The group sets the threshold, and how the stock trades — continuously or by auctions.
| Group | Static threshold | Trading | Stocks |
|---|---|---|---|
| 11 | ± 6 % | continuous | 47 |
| 12 | ± 4.5 % | auctions | 16 |
| 99 | ± 4.5 % | auctions | 12 |
Other groups and markets
The threshold does not depend on the company's size but on its trading group. For a Group 11 security, the threshold applied during an auction is 4%. Outside the main market, the appendix to the Règlement de parquet sets other static thresholds:
| Market | Static threshold |
|---|---|
| Alternative market (groups 52 and 95), at auction | ± 15% |
| Bonds, sukuk and funds | 10% |
| Hors cote, group 13 | 3% |
| Hors cote, groups 23 and 24 | 10% |
The allocation between continuous trading and auction is reviewed every year: a security moves to continuous trading the following year if it records at least 1,200 transactions between 1st December and 30 November, with at least 300 transactions across at least two quarters of the period. A newly listed security moves to continuous trading at 500 transactions over 3 months.
What happens when a security is reserved
In continuous trading, the order that would trigger a reservation is partially executed within the thresholds; its remaining balance stays in the order book and the security is reserved upwards or downwards. The reservation lasts 10 minutes during the session; during trading at last price, 5 minutes, then 3, then 2 (see session trading hours).
At auction, the security is reserved until the next auction or until the following session.
During reservation, orders can still be entered. However, a day limit order whose limit falls outside the thresholds is prohibited (see order types).
If no price is possible within the static thresholds, trading remains reserved until the following session and the Stock Exchange displays an indicative closing price equal to the threshold. This is the price used in the calculation of the indices.
Three misconceptions
“A share does not move by more than 6% during the day.” The threshold limits the divergence from the reference price. Within a session, the spread between the low and the high can reach double that, from −6% to +6% for Group 11.
“A reserved security is reserved for a session.” A security can remain pinned to its threshold for several sessions in a row. The measurement presented below shows that no observed variation exceeds the threshold of its group.
“The dividend causes the share price to drop below the threshold.” On the ex-date (detachment), the reference price is adjusted: the mechanical drop due to the dividend does not consume the threshold (see how to read a dividend notice).
Special cases
- Newly listed securities (main market): during the first 2 sessions, a range of ±30% and a single auction per session; these rules cease as soon as a price is established in the first session. See IPOs and capital increases.
- Bonus rights: 25% during the first month of listing, then 250% (250% from the outset on the alternative market).
- Subscription rights: no threshold during their trading.
- Non-assimilated new shares: static thresholds of the parent line.
- Block market (off-book): from 1,000,000 DT (100,000 DT on LS lines), within a margin of ±10% around the last traded price, ±20% from 10 times this minimum.
Frequently asked questions
What is the reservation threshold on the Tunis Stock Exchange?
It is the maximum variation a price can reach relative to the reference price during a session. It is ±6% for the main market in continuous trading (group 11), ±4.5% for the main market at auction and ±15% for the alternative market.
Why is a share reserved on the upside?
Because a buy order cannot find a counterparty within the thresholds. It is partially filled at the threshold, its remaining balance stays in the order book, and trading is suspended for 10 minutes in continuous trading. If no price is possible within the thresholds, the security remains reserved until the following session.
What is the maximum daily variation of a share?
It depends on the trading group: ±6% in continuous trading, ±4.5% at auction on the main market, ±15% on the alternative market, always relative to the reference price.
What happens to an investor when a share is reserved on the downside?
Orders can still be entered during reservation. A day limit order whose limit falls outside the thresholds remains prohibited, and a market order may be filled at the threshold.
What is the difference between continuous trading and auction?
In continuous trading, orders are executed throughout the session (group 11, ±6%). At auction, they are matched at a set time and give a single price (groups 12 and 99, ±4.5%). The allocation is reviewed every year based on the number of transactions.
How we know
The exchange publishes no simple table of thresholds by group. So we MEASURED it on our own prices, by asking the only question that settles it: what goes beyond? A threshold that exists is never crossed — and the largest move observed gives it to the second decimal.
| Group | Moves observed | Largest observed | Beyond the threshold |
|---|---|---|---|
| 11 | 7,472 | 6.000 % | 0 |
| 12 | 1,573 | 4.500 % | 0 |
| 99 | 928 | 4.500 % | 0 |
Measured over 9,973 moves between consecutive sessions, from 15/05/2023 to 30/10/2026. The move used is the one the exchange publishes, not a ratio of two closes. This measurement corrected our own table: the auction groups were recorded at 4%, they are at 4.5%.
Sources
- Règlement de parquet de la Bourse de Tunis, applicable à partir du 28/09/2026, et son annexe — art. 4.3.2, 8.1.4, 8.2, 8.3, 8.4.2, 8.5.1 et annexe
- Règlement général de la Bourse — art. 92
- Bourse de Tunis — horaires de cotation — page web
- Mesure Mizen sur ses propres cours (séances consécutives), tableau « Comment nous le savons » — données Mizen
General information; not tax advice and not an investment recommendation.