Finance Minister Enoch Godongwana will present the 2026 budget bill to lawmakers on Wednesday.

Investors in Africa's economic powerhouse are watching closely to see whether the Treasury can keep debt levels stable and limit borrowing without fresh tax shocks.

Here are the key questions for investors:

WHAT ARE THE DEFICIT, PRIMARY SURPLUS AND DEBT PEAK SIGNALS?
Rising prices of South Africa's exports - including gold and other metals - have boosted revenues, and Morgan Stanley's economist Andrea Masia said Godongwana's budget "could be one of the most bullish budget documents prepared by National Treasury in many a year".

The document could provide a window into the durability of the revenue strength and how much of it the Treasury chooses to include into the baseline.

National Treasury is likely to narrow this year's fiscal deficit forecast slightly from 4.5% to 4.4% of GDP, according to Goldman Sachs. In primary terms, excluding debt interest payments, this amounts to a surplus of 1.0% of GDP, the bank said.

WHAT'S THE TAX PLAN?
Surging metals prices and stronger household consumption have boosted coffers, while political pressures limit tax increases.

For BNP Paribas, there will be "little-to-no debate on tax rises yet".

Markets will scan for changes to personal income tax brackets, medical credits and excise duties that could raise revenues even if the value-added tax and headline income tax rates are unchanged.

Nedbank said the tax windfall could give the Treasury some leeway to tweak pay-as-you earn tax brackets that were not adjusted for inflation in the past two years.

A FISCAL RULE OR ANCHOR
The budget could include an expenditure-capping framework, anchoring spending to revenue growth.

In its annual economic check-up earlier this month, the International Monetary Fund said spending ceilings introduced in 2012 have not prevented debt from rising, and urged clearer and more binding limits that can outlast the current political cycle.

WILL FIXED-RATE LOCAL-BOND ISSUANCE FALL?
Local bonds have rallied in recent weeks, with long-dated debt yields dropping to ten-year lows on optimism over rising revenue, but investors will closely scrutinise the borrowing tables and auction guidance.

JPMorgan said it expects "an over 50% chance of another fixed-rate South African government bond issuance cut," potentially to R2.5-billion a week, from the R3-billion currently.

GFECRA AND FOREIGN BONDS
The government could also use the Gold and Foreign Exchange Contingency Reserve Account (GFECRA) that captures gains or losses on foreign exchange holdings to limit borrowing while taking advantage of gold price increases.

Nedbank also expects Treasury to issue more foreign bonds to meet $4.3-billion of external maturities in the 2027 financial year.