LAST year Indonesia’s finance minister, Sri Mulyani Indrawati, invited chief executives, directors and shareholders from the country’s leading industries to banquets at her ministry. As they munched, she would give presentations setting out who among them had—and, by omission, who had not—signed up to the government’s tax amnesty. “This may be the most expensive dinner in your lifetime,” the 54-year-old economist recalls telling them.

Indonesia’s tax amnesty, which began in July 2016, ended on March 31st. More than 800,000 evaders declared 4,700trn rupiah ($350bn) in assets previously hidden from the authorities. That is a staggering sum, equivalent to 40% of Indonesia’s GDP and 90% of the money supply, and revealing of the epic scale of tax-dodging.

The willingness of tax cheats to come clean partly reflects the generous terms on offer. Assets declared in the first three months were taxed at just 2-4%, compared with the individual income-tax rate of up to 30%. Those declared in the next three months were taxed at 3-6%, and those in the final three months at 5-10%. The government collected additional revenue of 125trn rupiah, equivalent to less than 3% of the total assets declared. The OECD, a club of mostly rich countries, has criticised the amnesty for rewarding tax cheats.

Maybe, but it was also one of the world’s most successful in terms of revenue raised. The money will help replenish government coffers at a time when revenues from commodities are still far below the levels in 2014, when prices for natural resources were at their highest. In recent years the government has cut spending to prevent its budget deficit from breaching a legal limit of 3% of GDP. This, in turn, is denting economic growth. Last year government spending shrank in real terms for the first time since the Asian crisis of the late 1990s; that is one reason why growth, at 5% in 2016, remains stubbornly below the government’s target of 7%.

But beyond the immediate revenue windfall, the success of the amnesty depends on whether it marks a lasting upturn in tax receipts. Only 30m people out of a labour force of 118m are registered with the tax office and only 10m of them file a tax return regularly. At around 10% of GDP, Indonesia’s tax ratio is one of the lowest in South-East Asia (see chart) and compares with an average of 34% among OECD countries. The government hopes that the amnesty will add new names to the tax register and thus bring about a steady increase in the numbers paying the tax they owe.

Ms Mulyani, praised for her fearless reforms as finance minister under the previous president, Susilo Bambang Yudhoyono, in 2005-10, says she aims to raise the tax ratio to 13% of GDP. Since returning to government in July 2016, after a stint at the World Bank in Washington, DC, she has set up a “reform team” at her ministry to improve procedures, introduce new technologies and recruit more auditors.

In January Indonesia signed up to an OECD scheme known as the Common Reporting Standard. Signatories, including many of the havens where Indonesians traditionally stash their wealth, such as Singapore, have agreed to share information on foreign account-holders. Indonesia’s government is also pushing a law to make it easier for the tax office to probe domestic bank accounts.

Ms Mulyani’s previous reformist stint as finance minister came to an end after a feud with a politically connected tycoon. This time, with the support of the current president, Joko Widodo, she seems determined to continue where she left off. “Pay tax and pay it properly,” she says. “This time we really mean it.”