Brazil Tender Offer Disclosures API: Track OPA and Takeover Notices from CVM Filings

The problem

Takeover monitoring on B3 issuers splits into two stacks that search results often confuse:

1. Execution and market data — live prices, implied control premiums, sometimes deal calendars from sell-side research. Useful for trading, not for the filing text that defines price, acceptance conditions, and regulatory references.
2. Regulatory disclosures — fatos relevantes when an OPA launches, changes, or closes, and avisos aos acionistas when assemblies or formal notices frame the transaction for holders.

Scraping the CVM portal works for one ticker and breaks on a multi-name watchlist. Bulk open-data ZIPs are dataset-oriented, not ticker-first. You want GET /v1/documents with stable document.id, then GET /v1/documents/:id/file for the original PDF — the same pattern as Brazil IPE disclosures, scoped to control transactions.

For equity issuance and dilution, see Brazil follow-on offering disclosures API. For treasury repurchases, see Brazil share buyback disclosures API. For the generic poll loop on all material facts, see Brazil material facts monitoring API.

Which filing type carries the tender offer?

Brazilian issuers do not expose a dedicated type=OPA in the apicvm document list. Tender offers and control events usually surface under:

Practical rule: poll both types for each ticker on your watchlist, then filter rows by name keywords (OPA, Oferta, aquisicao, controle, alienacao) before downloading PDFs. After download, search PDF text for oferta pública de aquisição, preço da oferta, or aceitação.

Step-by-step list queries for material facts: List fatos relevantes via API. Reference for avisos: List avisos aos acionistas via API.

On VALE3 for calendar year 2025, the demo corpus included a FATO_RELEVANTE row whose name references aquisição of participative debentures with dateRef 2025-11-05 (demo API, queried 2026-09-13). That row illustrates acquisition-related material facts on the IPE feed; live OPA launches on banks and mid-caps use the same list-and-download pattern with OPA / oferta tokens when present in the corpus. Zero rows in a given year does not prove no tender offer occurred — see limitations below.

How apicvm helps

1. Resolve the issuer — GET /v1/companies/resolve
2. List event filings — GET /v1/documents with types=FATO_RELEVANTE,AVISO_AOS_ACIONISTAS
3. Scope with year and optional dateRef; sort with field=dateRef&order=desc
4. Download the PDF — GET /v1/documents/:id/file (no extraction credits)
5. Optional (Pro): page-level markdown — POST /v1/document-text-extractions with async callback

Auth: Authorization: Bearer or X-API-Key. Try VALE3 without a key via the demo API.

Setup

export APICVM_KEY='apicvm_...'
export APICVM_URL='https://apicvm.dev'

Step 1: List material facts and shareholder notices

curl -H "Authorization: Bearer $APICVM_KEY" \
  "$APICVM_URL/v1/documents?ticker=VALE3&types=FATO_RELEVANTE,AVISO_AOS_ACIONISTAS&year=2025&perPage=50&field=dateRef&order=desc"

Response rows include stable id, dateRef, name, and nested company metadata. Use id as your cache key — not name, which can be long and encoding-sensitive.

Paginate with page= when meta.lastPage > 1. perPage maxes at 50.

Step 2: Narrow to OPA and takeover rows

Filename tokens on the CVM IPE feed are predictable enough for a first-pass filter:

curl -s -H "Authorization: Bearer $APICVM_KEY" \
  "$APICVM_URL/v1/documents?ticker=VALE3&type=FATO_RELEVANTE&year=2025&perPage=50" \
  | jq '.data[] | select(.name | test("OPA|Oferta|aquisicao|controle|alienacao"; "i")) | {id, dateRef, name}'

After download, search PDF text for oferta pública, ações em circulação, or prazo de aceitação for validation. Extraction credits apply only if you use the text-extraction endpoint.

Step 3: Download a tender offer notice PDF

curl -H "Authorization: Bearer $APICVM_KEY" \
  -o tender-offer-notice.pdf \
  "$APICVM_URL/v1/documents/<document-id>/file"

Download does not consume extraction credits.

Example: Python watchlist for OPA filings

Poll material facts across a control-focused watchlist. Persist seen in your database in production.

import os, time, requests, re
from datetime import datetime

BASE = os.environ["APICVM_URL"]
H = {"Authorization": f"Bearer {os.environ['APICVM_KEY']}"}
WATCH = ["VALE3", "PETR4", "ITUB4", "BBDC4", "ABEV3"]
YEAR = datetime.utcnow().year
OPA_RE = re.compile(
    r"OPA|oferta|aquisicao|controle|alienacao|takeover", re.I
)
seen = set()  # load from your store on startup

def list_event_filings(ticker):
    r = requests.get(
        f"{BASE}/v1/documents",
        headers=H,
        params={
            "ticker": ticker,
            "types": "FATO_RELEVANTE,AVISO_AOS_ACIONISTAS",
            "year": YEAR,
            "perPage": 50,
            "field": "dateRef",
            "order": "desc",
        },
    )
    if r.status_code == 429:
        time.sleep(5)
        return list_event_filings(ticker)
    r.raise_for_status()
    return r.json()["data"]

for ticker in WATCH:
    for doc in list_event_filings(ticker):
        if doc["id"] in seen:
            continue
        if not OPA_RE.search(doc.get("name") or ""):
            continue
        seen.add(doc["id"])
        print(f"OPA {ticker} {doc['dateRef']} {doc['name'][:70]}")

Wire this into GitHub Actions CVM monitor or extend the diff pattern from Brazil material facts monitoring API.

OPA events vs periodic M&A diligence

Brazil regulatory filings API explains the full layer map. During earnings windows, pair this hub with Track Brazil earnings season for ITR alongside event filings.

Current limitations

• Documents, not execution — apicvm does not route bids, accept tender instructions, or return CVM registration status as an API field.
• Keyword filters are heuristic — name tokens help; false negatives are possible if issuers use unusual titles.
• Polling, not push — no webhook when CVM publishes a new fact. Schedule polls and diff document.id.
• Ingestion lag — sync is not real-time. A notice may appear on the portal before it is in the corpus.
• Corpus coverage — not every issuer or period is present. Validate against the portal for production compliance use cases.
• Demo scope — /v1/demo/* is limited to VALE3. Other tickers need a production key.

Next steps

• Read the API docs
• Get an API key
• List fatos relevantes — focused FATO_RELEVANTE reference

Related guides

• Brazil follow-on offering disclosures API — capital increases and subscription rights
• Brazil share buyback disclosures API — treasury repurchases
• Brazil dividend disclosures API — payouts and JCP
• Extract text from CVM PDFs for AI agents — async markdown extraction
• Build a multi-ticker CVM filings watchlist