Investors take note: The week's winners and losers on Borsa Istanbul

Last week, the BIST 100 index on Borsa Istanbul saw a low of 11,250.46 points and a high of 11,470.03 points between December 15 and 19, 2025. The index's performance was influenced by developments in international markets, while variations occurred on a stock and sector basis.

While the banking index gained 1.71 percent and the holding index rose by 0.63 percent, the industrial index lost 0.24 percent in value.

THE WEEK'S WINNERS AND LOSERS

Among the companies in the BIST 100 index, Türk Altın İşletmeleri (TRALT) was the top gainer of the week with a 12.59 percent increase in value. It was followed by Efor Yatırım (EFOR) with an 11.16 percent gain and Margün Enerji (MAGEN) with a 10.10 percent gain.

On the other hand, Gen İlaç (GENIL) lost 15.24 percent, Tüpraş (TUPRS) lost 6.58 percent, and Çan2 Termik (CANTE) lost 6.14 percent, ranking among the stocks that fell the most during the week.

COMPANIES WITH THE HIGHEST MARKET CAPITALIZATION

Among the companies with the highest market capitalization on Borsa Istanbul, ASELSAN (ASELS) ranked first with 962 billion 616 million TL. It was followed by Garanti BBVA (GARAN) with a market capitalization of 596 billion 400 million TL and Enka İnşaat (ENKAI) with 469 billion 500 million TL.

MOST ACTIVELY TRADED STOCKS

Last week, the trading volume in the BIST 100 index saw a slight decline, reaching 481 billion 56 million TL. Türk Hava Yolları (THYAO) was the most actively traded stock with 39 billion 876 million TL. It was followed by Türk Altın İşletmeleri (TRALT) with a trading volume of 29 billion 493 million TL and İş Bankası (ISCTR) with 27 billion 119 million TL.

News Source: 12punto