The rationalisation in the goods and services tax rates last September delivered a larger-than-expected expansion in the tax base, with higher taxable supplies more than offsetting the revenue foregone from lower tax rates, according to a government analysis. Average monthly taxable supply, an indicator of revenue for businesses, grew 22.5% in the second half of FY26 (after GST changes on September 22). As the levy completes nine years on July 1, a look at the impact of last year’s changes.