1. Definition
A bank's investment portfolio holds the securities it acquires to keep over time: Treasury bills and bonds, other bonds, equity holdings. It is distinct from the trading portfolio, made of securities bought to be sold in the short term. The investment portfolio share divides the income from these securities by total banking operating income: it says what share of what the bank takes in comes from the securities it holds over time.
In French, it is called the portefeuille d'investissement.
2. The measure
The investment portfolio share follows one formula, the same for every bank: income from the investment portfolio divided by total banking operating income for the half-year.
Example, the bank where this share is highest: STB, in the first half of 2026: its securities bring in 32.6% of its banking operating income.
A high share says a bank whose income depends heavily on its securities, often government ones; a low share, a bank that lives mainly on its loans and fees.
3. Why it matters
It shows where income comes from. Two banks with the same NBI can draw it, one from its customers, the other from its investments.
It also shows an exposure. A bank heavily invested in Treasury securities ties part of its income to the State and to the rates it pays.
4. What it does not say
It does not say the size of the portfolio. A high share can come from a large portfolio, or from modest loan income next to it.
It does not say the risk of the securities. It separates neither interest from dividends, nor government securities from equity holdings.
5. Where to read it in Tunisian financial statements
Income from the investment portfolio is read in the income statement, item PR4. Total banking operating income is read just below, in the same statement.
The amounts are taken as published, for the half-year.
6. Three reading traps
First trap: the trading portfolio is not in it. Gains on trading securities and foreign exchange form another item (PR3); only income from the investment portfolio counts here.
Second trap: a rising share does not always mean the bank invests more. It also rises when loan income falls.
Third trap: the half-year matters. Dividends on equity holdings are often paid after shareholders' meetings, in spring; a first half can carry more of them than the second.
7. Ranking of the 10 listed banks by investment portfolio share, first half of 2026
The banks are ranked from the highest value to the lowest, amounts in millions of dinars:
| Rank | Bank | Portfolio income (TND m) | Operating income (TND m) | Investment portfolio share |
|---|---|---|---|---|
| 1 | STB | 216.3 | 663.6 | 32.6% |
| 2 | BNA | 394.4 | 1 233.7 | 32.0% |
| 3 | Amen Bank | 189.3 | 670.5 | 28.2% |
| 4 | Attijari Bank | 145.6 | 613.1 | 23.8% |
| 5 | BIAT | 293.6 | 1 270.3 | 23.1% |
| 6 | BH Bank | 157.6 | 694.5 | 22.7% |
| 7 | BT | 74.8 | 476.9 | 15.7% |
| 8 | ATB | 54.8 | 362.1 | 15.1% |
| 9 | UBCI | 21.2 | 306.5 | 6.9% |
| 10 | UIB | 22.1 | 451.3 | 4.9% |
Out of scope: BTE (preferred dividend shares) and Wifak International Bank (an Islamic bank).
The investment portfolio share ranges from 4.9% to 32.6% of banking operating income depending on the bank. Across the 10 banks together, it reaches 23.3%.
Key points
- Investment portfolio share = income from the investment portfolio (PR4) divided by total banking operating income.
- It says where income comes from, and the part tied to securities, often government ones.
- It is read with loan income, and over comparable half-years.
Read also: cost-to-income ratio of a bank, what net banking income and net profit do not say, the method of the series.
Sources: interim individual financial statements at 30 June 2026 published with the Conseil du marché financier (CMF), notes included.