Mistakidis worked for six years trading in non-ferrous metals for
Cargill. In 1993, he joined Marc Rich & Co in 1993, shortly before there was a management buyout and it was renamed
Glencore. He worked in the zinc, copper and lead department, rising to become a co-director in 2000. He became a billionaire with the May 2011 Glencore IPO. In December 2018, Mistakidis retired from Glencore, after he was fined C$2.45 million, and banned as serving as a director for four years in Ontario for false accounting in the Katanga Mining subsidiary. Ever since, he has expanded his business endeavors by building a diversified portfolio with emphasis on shipping, real estate, and banking. Mistakidis entered the shipping industry in 2021. Since 2021 he has expanded his real estate portfolio in Greece, the UK, and the US. Only in the USA a conservative estimation speaks of an investment of half billion dollars. During 2021, Mistakidis along with US billionaire
John Paulson invested in Greece's second largest bank
Piraeus Bank. He held a 5.14% stake in the bank. Mistakidis highlighted his confidence in the Greek national economy in the investment worth 50 million euros. In April 2024, he acquired a controlling stake in Aegean Baltic Bank (ABBank) by purchasing 48% of its shares, effectively securing 68% control over the bank. At the time of acquisition, ABBank reported assets of €1.15 billion, customer deposits of €1 billion, and loans totaling €505 million.
The Sunday Times Rich List 2022 reports Mistakidis net worth being £2.153 billion. As of June 2025, he has agreed to fund the New
Toumba Stadium project of
PAOK. From November 26, 2025, the company Alpha Sports Group Single Member SA of
Aristotelis Mistakidis interests is officially the owner of
PAOK BC. Mistakidis appeared for first time on the
Forbes Billionaires List in 2011 and today his net worth is estimated at US$3.1 billion. ==Personal life==