# Borsa İstanbul market activity and ownership shifts

> Live situation record from CLSTR: https://clstr.news/situations/borsa-istanbul-market-activity-and-ownership-shifts
> Updated: 2026-09-02T15:32:00.000Z. Sources: 4. Developments: 2.

Borsa İstanbul has experienced significant shifts in ownership and trading activity. In mid-August, a major change occurred at Akçansa when Sabancı Holding transferred its 39.72% stake to Heidelberg Materials AG, resulting in the latter holding a 79.44% majority stake. This shift triggered a mandatory tender offer requirement, pending decisions from the Capital Markets Board (SPK).

During this period, certain stocks saw massive surges in transaction volumes, with some companies reporting increases exceeding 1,000%. By early September, market activity continued through various share transactions and buybacks. Notable movements included stake increases by individual investors in companies such as AKSGY and GRTHO, as well as share buybacks by BSOKE and DAGI.

## Timeline

### 2026-09-02: Borsa İstanbul reports various share transactions and buybacks

Borsa İstanbul reports various share transactions and buybacks, including significant stake changes in AKSGY and GRTHO, while TR Anadolu Metal Madencilik saw daily trading volume of 0.75 billion TL.

4 sources. https://clstr.news/cluster/borsa-istanbul-reports-various-share-transactions-and-buybacks

### 2026-08-17: Borsa İstanbul sees ownership shifts and high trading volumes

Borsa İstanbul sees major developments as Heidelberg Materials becomes the dominant shareholder in Akçansa, triggering a mandatory tender offer, alongside surges in trading volumes for several BIST stocks.

2 sources. https://clstr.news/cluster/borsa-istanbul-sees-ownership-shifts-and-high-trading-volumes

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Cite as: Borsa İstanbul market activity and ownership shifts. CLSTR, https://clstr.news/situations/borsa-istanbul-market-activity-and-ownership-shifts