Tanzania's banking sector closed 2025 with its strongest earnings on record, according to the Bank of Tanzania's consolidated income statement for the industry, extending a multi-year run of double-digit growth in lending income and profitability.

But a closer read of the figures by Bank of Tanzania (BoT) financial sector report 2025 shows one year — 2023 — breaks sharply and inconsistently from the trend, raising questions about how that year's data was reported or consolidated.

Interest income, the lifeblood of any bank's earnings, rose to 6.68trn/- in 2025, up from 5.80trn/- in 2024 — a 15 percent increase and the continuation of a run that has seen interest income more than double since 2020 (3.02trn/-). 

Net interest income — what banks keep after paying out interest on deposits and borrowings — climbed to 4.56trn/- in 2025 from 4.15trn/- in 2024, a roughly 10 percent gain.

Non-interest income, which includes fees, commissions, and trading gains, also grew steadily, reaching 2.41trn/- in 2025 versus 2.09trn/- in 2024, continuing a trend that has seen this revenue line more than double since 2020.

The bottom line reflects that momentum: net income after tax hit 2.23trn/- in 2025, up modestly (about 5 percent) from 2.13trn/- in 2024, but up more than five-and-a-half times from 397.9bn/- in 2020 — implying a compound annual growth rate of roughly 41 percent over five years. Pre-tax profit followed a similar arc, rising to 3.22trn/- in 2025 from 3.01trn/-  in 2024, and up from just 662.9bn/- in 2020.

Two lines worth watching for any banking system are provisioning and write-offs, since they signal how lenders are managing credit risk. Provisions for bad and doubtful debts have stayed relatively stable in the 390–397bn/- range in three of the last four years (2020, 2021, 2024, 2025), suggesting a fairly consistent approach to loan-loss coverage even as the loan book — and presumably income — has grown. 

Bad debts actually written off, by contrast, have been volatile: from a low of 13.7bn/- in 2024 to 246.2bn/- in 2025, an increase that bears watching as a signal of asset-quality strain even amid strong headline profitability.

The effective tax burden on banks has also eased somewhat. Income tax provisions consumed about 41 percent of pre-tax profit in 2020, but that ratio has drifted down to around 29–31 percent in 2024 and 2025 — closer to the statutory corporate rate — as profits have scaled up faster than the tax charge.

Non-interest expenses — the overhead costs of running a banking network, including staff, technology, and premises — rose to 3.28trn/- in 2025 from 3.01trn/- in 2024, an 8.8 percent increase. 

That's slower than the growth in both net interest income and non-interest income, which is why operating income — a broad measure of earnings before non-core items and tax — rose to 3.05trn/- in 2025, more than double the 1.37trn/- t recorded just three years earlier in 2022. 

In short, the sector has been growing revenue faster than costs, a sign of improving efficiency and scale economies industry-wide.

One year in this dataset does not fit the pattern, and the inconsistencies go beyond a simple dip in earnings. In 2023, the data shows interest expenses of 3.58trn/- — higher than in any other year, including 2025 — while interest income that year (4.57trn/-) grew normally, producing a net interest income of just 114bn/-, a small fraction of the 2.89trn/- recorded the year before.

Non-interest income recorded as nil (shown as "–"), which would be unprecedented for a banking sector of this size and is inconsistent with steady growth in that line in every other year.

Non-interest expenses of only 40bn/-, roughly 1.7 percent of the 2022 or 2024 levels — implausible for an industry with dozens of banks and branch networks.

An income tax provision of 59.2bn/- against a pre-tax profit of only 9.3bn/- — mathematically, that would produce a net loss after tax, yet the table records a positive net income after tax of 4.2bn/-.

A one-off "extraordinary credits and charges" entry of 816.2bn/-, the only year in the six-year series in which this line is populated, alongside an unusually large "non-core credits/charges" figure of 1.26trn/-.

Taken together, these figures are internally inconsistent — the tax and profit lines alone don't reconcile — and don't fit the smooth growth pattern shown in every other line, in every other year.