São Paulo ICMS Mafia: Prosecutors Charge Former No. 3 of State Finance Secretariat — What Changes Now
Key Facts
Thirteen months after the first raid, São Paulo’s tax-credit corruption investigation has reached the upper ranks of the state finance secretariat — and the formal charges now move from the prosecutors’ office to a judge.
The São Paulo ICMS mafia case entered a new phase on Friday, 18 September 2026. The Ministério Público de São Paulo (MP-SP), the state prosecutor’s office, filed formal charges against four men accused of turning the release of state tax credits into a paid service for large retail companies.
At the top of the list is André Weiss, former head of the tax administration directorate at Sefaz-SP, the state finance secretariat. Brazilian outlets describe him as the former “number three” of the secretariat under Governor Tarcísio de Freitas. Prosecutors say he led the public side of the scheme.
Also charged are tax auditors Artur Gomes da Silva Neto and Kunio Shimada, and tax lawyer João André Buttini de Moraes. The complaint was presented by five prosecutors from GEDEC, the prosecutor’s specialised unit for economic crimes, according to the MP-SP statement.
The Charge and the Charged
The complaint assigns different crimes to different defendants. Weiss faces accusations of passive corruption and criminal organisation; Artur Gomes, of passive corruption; Shimada, of passive corruption and criminal organisation; and Buttini, of active corruption, money laundering and criminal organisation. The alleged conduct runs from 2021 to 2025.
According to the MP-SP’s statement, the group turned administrative acts tied to reimbursement requests for ICMS-ST into an illicit business. ICMS is the state sales tax on goods and services; ICMS-ST, or “substituição tributária”, is a mechanism in which tax is collected earlier in the supply chain, generating credits that companies later claim back.
Those refunds can take years under regular review. Prosecutors say the defendants charged companies a percentage of the credits they wanted released. They identified R$6.3 million (about US$1.2 million) paid in cash, plus invoices for services never rendered that allegedly hid part of the money. The reimbursement requests named in the complaint total more than R$390 million (about US$76 million).
The investigation that led to Weiss’s arrest found that Buttini passed about R$13.6 million (about US$2.6 million) in bribes between mid-2021 and August 2025, money prosecutors say was destined for Weiss. Around R$4.5 million (about US$874,000) was allegedly delivered in cash, in backpacks, at meetings in restaurants and other venues in Pinheiros, a west-side district of the state capital, SBT News reported, citing the MP-SP. The real traded at roughly 5.15 per US dollar on 18 September, mid-market rate.
The proceedings run before the 1st Court for Tax Crimes, Criminal Organisation and Money Laundering of the state capital, according to a statement from Shimada’s defence. The investigation grew out of criminal inquiry No. 18/2025 and drew on a plea-bargain agreement, searches, lifted bank and tax secrecy, phone data and ambient recordings, the MP-SP said.
Three of the four defendants are in preventive detention. Prosecutors asked the court to keep them there and to detain Shimada as well. The MP-SP stressed that the complaint is a formal accusation, not a verdict. A judge must still accept it. The defendants keep the presumption of innocence and the right to a full defence. Maurício Zanoide de Moraes, who represents Buttini, said the defence had not yet received the case files and respects the court-ordered secrecy. The other defences had not commented publicly by Friday afternoon, São Paulo time.
A Case Built in Three Operations
Friday’s charges crown a sequence of operations that has widened for over a year.
It began with Operação Ícaro in August 2025, which targeted fraud involving the pharmacy chain Ultrafarma and the electronics retailer Fast Shop. That phase brought preventive arrests of company executives. Investigators identified Artur Gomes da Silva Neto, then a state auditor, as the scheme’s architect. A bookkeeping firm called Smart Tax, registered in the name of his mother, issued more than R$1 billion (about US$194 million) in invoices that prosecutors say legitimised bribe money, Metrópoles reported.
In March 2026, Operação Fisco Paralelo served 22 search warrants in four cities. It arrested one fiscal agent and targeted auditors with unexplained wealth, including one whose home held a wine cellar valued above R$300,000 (about US$58,000) and gym equipment estimated at R$1 million (about US$194,000). Seizures in that phase included R$725,955 (about US$141,000) in cash. Messages recovered from phones treated bribes in code — words like “coffee” or “vitamins” — with values converted at the dollar exchange rate, G1 reported.
On 3 September, Operação Caldarium ordered the preventive detention of Weiss and Buttini, the phase The Rio Times covered when the São Paulo fraud actions first became public. Retailers Casas Bahia, Assaí and Dia appear in the reporting as companies whose credits benefited from the scheme; none of them is a criminal defendant in this complaint.
The corporate side carries its own bill. Fast Shop, which prosecutors say received R$936.4 million (about US$182 million) in advantages, agreed to pay a fine of R$1.04 billion (about US$202 million) — the largest penalty applied under Brazil’s Anticorruption Law in São Paulo state.
The Auditor Who May Still Be Inside
One detail in Friday’s filing is contested. Prosecutors say Kunio Shimada, a fiscal agent at a São Paulo regional tax office, continues to work in the same function he held during the alleged scheme. Inside the group, investigators say, he was known as “Chief K”. The complaint accuses him of receiving 10 percent of the bribes and of taking part in eight reimbursement requests for Ultrafarma totalling almost R$100 million (about US$19 million), Metrópoles reported.
Sefaz-SP disputes the premise. In a statement, the secretariat said Shimada has been removed from his post, without pay, since 26 March, with his system access blocked, and faces an administrative process that can end in dismissal. His lawyers add that a court ordered those measures in March and that he has complied fully. They call the new detention request unjustified. Which account describes his actual day-to-day status is, for now, a matter of competing claims.
The Institutional Response
The secretariat says the fallout has already changed the institution. Five employees have been dismissed, one exonerated and 23 suspended without pay. Forty-five auditors are under internal investigation by the tax oversight unit. Tax assessments tied to the case have constituted more than R$3 billion (about US$583 million) in credits, including fines and interest.
Sefaz-SP also says it has removed more than 62 percent of products from the substituição tributária regime — the mechanism at the heart of the fraud — and expanded the use of artificial intelligence in its audit filters. That simplifies taxation, but it also narrows the space in which the alleged scheme operated.
What It Means for Foreign Residents and Businesses
For expats and investors, this case is less about one secretariat than about how Brazil’s largest state economy polices itself. São Paulo collects more ICMS than any other state, and the reimbursement queue touches every retailer, importer and manufacturer operating there.
Companies that paid for speed now face assessments, fines and anti-corruption exposure. Companies that waited in line legally absorbed the cost of delay. The correction underway — dismissals, a record state fine, a simpler tax mechanism — points towards cleaner administration, but it will run for years, not weeks.
The longer arc matters too. Brazil’s 2023 tax reform will gradually fold ICMS into a dual value-added tax system, with the transition running to 2033, and is designed to shrink exactly this kind of credit bureaucracy. Cases like this one are part of why that reform gathered support.
What Is Not Known
The court has not yet accepted the complaint, and no trial date exists. Whether the judge has ruled on the fourth detention request was not confirmed by Friday evening. The full defences of Weiss, Artur Gomes and Buttini have not been presented publicly. And because the complaint draws on a plea-bargain agreement, further charges against other officials or companies remain possible. The MP-SP has not given a final total for the scheme’s damage.
The next milestone is procedural and unglamorous: a judge reading the files and deciding whether this becomes a criminal case. That is how accountability inside a tax authority actually advances — one accepted complaint at a time.
Frequently Asked Questions
Who was charged in the São Paulo ICMS mafia case on 18 September 2026?
State prosecutors charged four men: André Weiss, former head of the tax administration directorate at the São Paulo finance secretariat; tax auditors Artur Gomes da Silva Neto and Kunio Shimada; and lawyer João André Buttini de Moraes. The case file combines active and passive corruption, money laundering and criminal organisation, in different combinations per defendant.
What was the alleged scheme?
Prosecutors say the group charged companies a percentage of the ICMS-ST tax credits they wanted released. They traced R$6.3 million (about US$1.2 million) in cash payments and false invoices, against reimbursement requests exceeding R$390 million (about US$76 million).
Is one of the accused still working at the tax authority?
That is disputed. Prosecutors say auditor Kunio Shimada remains active in his function. The finance secretariat says he has been suspended without pay since 26 March, and his defence says he has complied with all court-ordered restrictions since then.
What happens next in court?
A judge must decide whether to accept the complaint and turn it into a criminal case, and whether to order preventive detention for the fourth defendant. Three defendants are already detained.
What does the case mean for companies operating in São Paulo?
Companies named in the investigation face tax assessments and fines — more than R$3 billion (about US$583 million) in credits have already been constituted, and Fast Shop agreed to a R$1.04 billion (about US$202 million) fine, the largest under the Anticorruption Law in São Paulo state. The secretariat says it has removed 62 percent of products from the tax mechanism at the centre of the fraud.
Sources: SBT News on the formal charges and the MP-SP statement, Metrópoles on the auditor’s disputed status and the defence statements, G1 on Operação Fisco Paralelo, O Globo on the 18 September complaint, Agência Brasil on Operação Caldarium
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