fon.org.tr TEFAS Fund Data
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Browser Extension Privacy Policy

Last updated: July 24, 2026

This policy covers the Fon.org.tr browser extension. How the website itself handles your data is covered separately, and linked at the bottom of this page.

Stored on your device

The extension keeps the following in your browser's extension storage. It stays on your device and is never sent anywhere except back to fon.org.tr:

  • The fund codes you pinned, so your list is waiting each time you open the popup.
  • Your display preference — which benchmark returns are adjusted by: official inflation (CPI), ENAG, the US dollar, the dollar plus US inflation, or the euro.
  • If you sign in, the session token issued by fon.org.tr. It is what keeps you signed in, and signing out deletes it.
  • A short-lived cache of fund quotes, price series, the inflation and exchange-rate series, and the extension's configuration — so reopening the popup does not re-request identical public data.

Sent to fon.org.tr

fon.org.tr is the extension's only data source and the only server it ever contacts. It receives:

  • The fund codes you are looking at, so it can return their prices and returns.
  • If you are signed in, an authorization header carrying your session token.
  • If you use the right-click “Search fon.org.tr” item, the text you selected — as the search term in the address that opens.
  • The ordinary information any web request carries, such as your IP address and browser user-agent.

Never collected

The extension ships with no instrumentation of any kind:

  • No analytics, no telemetry, no session recording, no crash reporting.
  • No advertising, no trackers, no third-party scripts. Nothing is sold or shared with anyone.
  • No location, no health data, no payment details, no personal communications.
  • No browsing history — the extension cannot see which pages you visit.

It does not read the pages you visit

The extension ships no content scripts and requests access to no website other than fon.org.tr — not even tefas.gov.tr. It never injects anything into a page, never reads a page's contents, and never changes what you see. The single exception is text you deliberately select and send yourself, using the right-click search item.

Removing your data

  • Sign out from the popup — this deletes the session token from your device.
  • Uninstall the extension — your browser clears everything it stored, including pins, preferences and cached data.
  • Your fon.org.tr account itself, including favorites and active sessions, is managed on the website under My account.

The website

How fon.org.tr itself handles data — including the cookies and analytics used on the site, none of which the extension uses — is covered by our Terms & Privacy Notice and Cookie Policy.

Contact

For privacy questions about the extension, write to [email protected].