Short answer: MKK (Merkezi Kayıt Kuruluşu), the Central Securities Depository & Trade Repository of Türkiye, keeps the electronic record of Turkish capital market instruments and the rights attached to them. Investors never hold an account directly at MKK: a member firm opens it, and each investor gets one registration number. As of 6 November 2026, equities stay in segregated accounts and pooled omnibus accounts are allowed only for government debt securities.
Custodians, operations staff and fintech teams usually meet MKK through a practical question: who holds the official record, how far down does it go, and what can a foreign institution see? MKK's English site lists services without much explanation, so this guide connects them.
Everything was checked on MKK's and other official pages on 6 November 2026. It recommends no broker, custodian or route. Home-country rules on custody, reporting and tax can add obligations, so check them separately.
What is a central securities depository?
A central securities depository (CSD) keeps securities as book entries and services the rights attached to them, so ownership changes on its records rather than by moving paper.
The European Central Bank's glossary describes a CSD as an entity that enables securities transactions to be processed and settled by book entry, provides custodial services such as administering corporate actions and redemptions, and plays an active role in ensuring the integrity of securities issues. Article 80 of Capital Markets Law No. 6362 defines central custody institutions in similar terms and names MKK as the one for dematerialized instruments (Article 80(3)); Article 81 sets out MKK's duties.
| Role | Who | What it does |
|---|---|---|
| Central securities depository | MKK | Official electronic record by member and right holder |
| Clearing house and central counterparty | Takasbank | Nets trades and guarantees settlement between members; for the current cycle and the T+1 project, see Borsa Istanbul T+1 settlement |
| Broker, bank or custodian | Firms authorized by the Capital Markets Board | Holds the client relationship and opens the account at MKK |
In its 2025-2026 questionnaire for global custodians (opens in a new tab), MKK states that securities cannot be removed from the depository once dematerialized, so there is no paper certificate to fall back on.
MKK's legal role, owners and supervision in Turkey
MKK is a private joint-stock company with duties set by law, supervised by the Capital Markets Board (SPK) and owned by market institutions.
- Core job (Article 81/1). Dematerialize instruments, track them and their rights electronically by member and right holder, and keep central custody.
- Other jobs (Article 81/3). A platform for communication between companies and investors, a central capital markets data bank, and electronic warehouse receipts.
- Liability (Article 81/5). MKK and its members answer for losses from wrong records in proportion to their fault.
- Supervision. SPK under Article 81/6. The 2025-2026 questionnaire adds that the Central Bank of the Republic of Türkiye regulates payment and securities settlement system operators, including MKK.
- Owners. The same questionnaire lists Takasbank at 64.9%, Borsa Istanbul at 30.1% and the Turkish Capital Markets Association at 5%.
Article 13 makes electronic issue the rule and requires dematerialized instruments to be tracked in accounts opened in the holder's name unless the Board allows otherwise. On scale, MKK's data platform VAP showed 39.24 million registered investors (12.78 million with a balance, a count that VAP says has included crypto asset investors since 6 August 2026) and 95.18 million registered accounts (15.72 million with a balance) when read on 6 November 2026, on a page with a market date of 4 November 2026.
The investor registration number and e-YATIRIMCI
Each investor gets one registration number, unique to that investor, and every account behind it is opened by a member firm.
MKK's account operations page says members open accounts and tag them with identity data, with checks integrated with the systems of the Ministry of Interior and the Ministry of Treasury and Finance, and that the system then generates a number that is separate and unique for each investor. Custody and protection for a retail buyer are covered in how to buy Turkish stocks; the points below add what a foreign reader tends to miss.
- What e-YATIRIMCI shows. MKK's investor service lists accounts and transactions at all institutions, pledges, securities lending, corporate actions and proxy registration for general meetings, plus an investor blockage you can apply for and release.
- How to log in. With an MKK registry number and password, or through e-Government authorization.
- Non-residents. The English page does not say whether non-residents can use it. The tariff of 26 February 2026 says that for investors located abroad who use MKK's information services, the password letter goes out as printed mail, priced at the shipping company's rate.
Omnibus accounts and links with foreign depositories
Omnibus accounts exist at MKK only for government debt securities, so Turkish equities remain in segregated accounts.
The basis is Article 12/A of the dematerialization communiqué, II-13.1 (opens in a new tab), added by amending Communiqué II-13.1.c (opens in a new tab) in Official Gazette No. 30809 of 22 June 2019, read with a Capital Markets Board decision limiting these accounts to government debt, according to MKK's omnibus page. That page labels the communiqué Serial IV, No. 62, while the Gazette and MKK's own copy of the text say II-13.1. Under Article 12/A, a foreign central securities depository holds the instruments on a nominee basis for right holders resident abroad and is deemed their fully authorized representative; it must sign a service contract with a bank holding a general custody license, and the two are jointly and severally liable to MKK. Investment institutions with general custody authority may offer non-resident owners custody on the same principles (Article 12/A(7)).
| Depository | Since | Scope |
|---|---|---|
| OeKB (Austria) | 2009 | Operational link for a dual-listed share, serviced through an MKK account at OeKB |
| Euroclear Bank | 2020 | Government debt securities |
| National Depository Center of Azerbaijan | 2022 | Government debt securities |
| Clearstream Banking S.A. | 2025 | Government debt securities |
| Central Securities Depository of Kazakhstan | 2025 | Government debt securities |
MKK and Clearstream's notice of 17 September 2025 says equities and corporate bonds continue through the existing segregated structure. What a bond holder sees in practice is in Turkish government bonds and eurobonds.
MDYS: account opening for non-resident institutions
The Central Document Management System (Merkezi Doküman Yönetim Sistemi, MDYS) is MKK's platform, launched in May 2026, for starting a non-resident's account opening digitally and sharing the documents with investment firms.
| Date | Step |
|---|---|
| 29 April 2025 | Amendment to the MKK Regulation published in Official Gazette No. 32885, giving MKK the mandate |
| 29 May 2025 | MKK announces the plan for non-resident account opening |
| 8 May 2026 | Member letter 1067 announces the system, with user manuals in Turkish and English |
| 13 May 2026 | MKK publishes the launch notice in English |
According to MKK's launch notice, a beneficial owner can begin digitally and submit physical documents later, send documents directly instead of by post or email, and share them with investment firms subject to the investor's approval. The notice also says this eases applications for a potential tax identification number for foreigners, while letter 1067 says integration with the Revenue Administration (GİB) for that step was still in progress on 8 May 2026.
The launch notice speaks of institutional investors, but the English user manual attached to letter 1067 also sets out registration for real persons resident abroad; for a company, entering its LEI pulls some data from GLEIF. The manual leaves the approval or rejection of each application to the investment firm. MKK's pages do not say whether MDYS changes a firm's own know-your-customer checks or which documents a given firm will still ask for, so ask the firm opening the account. Using MDYS does not remove the need for an authorized firm.
MKK fees: what the 26 February 2026 tariff says
MKK's tariff charges fees monthly on a member basis, so a tariff line shows what a firm owes MKK and not what a client pays.
| Line | Amount | Note |
|---|---|---|
| Account opening | TRY 17.7492 | Per account opened by a member; 20% more when entered by screen or CSV |
| Investor information service | TRY 55.6841 | For an investor registered for the first time; charged again if the password is requested again |
| Account maintenance | TRY 0.1091 a day | Accounts with a custody balance of TRY 1,000 or more |
| Custody, free-float shares and ETFs | 0.8 per 10,000 a year | On market value, from daily balances |
| Exchange trade record | TRY 0.2083 | Per debit or credit record |
| Foreign CSD: membership entry | TRY 869,010 | Once, on application |
| Foreign CSD: annual dues | TRY 7,800 | From the year after membership |
| Foreign CSD: omnibus custody | 1 per 10,000 a year | On nominal value of permitted government debt |
| Foreign CSD: account management | TRY 348 a month | Per omnibus account |
Hypothetical example: one account holds free-float shares worth TRY 500,000 all year, with 20 exchange trade records. A member would owe MKK about TRY 39.82 in maintenance (365 x TRY 0.1091), TRY 40.00 in custody and TRY 4.17 in records, about TRY 83.99 before BSMV. What the client pays depends on the firm.
Firms set their own charges, and the tariff changes, so use the current file on MKK's tariffs page (opens in a new tab) rather than these lines for a live calculation; on 6 November 2026 its English and Turkish versions both still linked the 26 February 2026 file.
MKK Turkey entity search, member lists and VAP data
As read on 6 November 2026, MKK's site offers no tool called entity search; the nearest lookups are its member and securities lists, its e-ŞİRKET company portal, KAP's lists and Takasbank's identifier services.
| You want | Where | What it shows |
|---|---|---|
| A firm's MKK code | MKK List of Members | Code, member title, country, MKK name and code |
| A security's ISIN and MKK code | MKK List of Securities (opens in a new tab) | Exchange code, description, ISIN, MKK name and code |
| A Turkish company's mandatory website documents | MKK e-ŞİRKET portal | Public search by company title; MKK says it gathers what companies must publish online under Article 1524 of the Turkish Commercial Code |
| A company's or fund's filings | KAP | Company and fund lists with their notices |
| An LEI or ISIN assignment | Takasbank | It is an LEI issuer and the national numbering agency |
| Whether a firm is authorized | SPK's lists | Not an MKK question |
VAP (Veri Analiz Platformu), MKK's data platform with an English option, showed foreign investors with 37.32% of equity portfolio value, about USD 51.03 billion, and 33,054 foreign equity investors when read on 6 November 2026. Those lines carry no date of their own: the market screen shows 4 November 2026 and a notice on the page refers to the weekly close of 30 October 2026, so quote VAP with your read date.
MKK also runs an API Portal; access routes and terms are covered in TEFAS, KAP and EVDS data APIs.
Frequently asked questions
What does MKK stand for in Turkey?
Merkezi Kayıt Kuruluşu. Its English name is Central Securities Depository & Trade Repository of Türkiye, and Article 81 of Capital Markets Law No. 6362 sets out its duties.
Can I open an account directly at MKK?
No. A member firm, such as a broker or bank, opens the account, and the system generates your investor registration number. You can then follow balances through e-YATIRIMCI.
Are Turkish shares held in omnibus accounts?
No. As read on 6 November 2026, MKK says omnibus accounts may hold only government debt securities, and the MKK and Clearstream notice of 17 September 2025 says equities and corporate bonds stay in segregated accounts.
Does MKK charge investors directly?
Its tariff charges fees monthly to members. A firm may pass some or all of those fees to clients under its own price list, so check the firm's tariff and your statement.
What is the difference between a CSD and a custodian?
A central securities depository keeps the top-level book-entry record for a market. A custodian holds assets for clients and usually keeps accounts at the depository on their behalf.
Sources
- Capital Markets Law No. 6362, Articles 13, 80 and 81 (Turkish) (opens in a new tab)
- European Central Bank: glossary entry for central securities depository (opens in a new tab)
- MKK: Account operations, investor registration number (opens in a new tab)
- MKK: Omnibus accounts operations and foreign depository links (opens in a new tab)
- MKK: Communiqué II-13.1 on dematerialized capital market instruments, English text (opens in a new tab)
- MKK and Clearstream: direct access to Turkish capital markets, 17 September 2025 (opens in a new tab)
- MKK: Launch of MDYS for non-resident institutional investors, 13 May 2026 (opens in a new tab)
- MKK member letter 1067, 8 May 2026: Central Document Management System (Turkish) (opens in a new tab)
- MKK: Account opening process for non-resident investors, 29 May 2025 (opens in a new tab)
- MKK: Fee schedule of 26 February 2026 (opens in a new tab)
- MKK: e-Investor service (opens in a new tab)
- MKK: List of Members (opens in a new tab)
- MKK: e-ŞİRKET Companies Information Portal (opens in a new tab)
- VAP: MKK data analysis platform, market overview (opens in a new tab)
- Takasbank: Legal Entity Identifier service (opens in a new tab)
This guide is general information, not investment, legal or tax advice. Amounts, rates and rules in Turkey change often: check the date given for each figure and the official source before you rely on it, and ask a licensed adviser about your own situation. Sources, checks and corrections: see the editorial policy.