Thomas and Andreas Struengmann built one of the world’s biggest fortunes over the past four decades in medicine and health care, partly due to an early bet on a maker of Covid-19 vaccines.

A private equity giant has also increasingly helped shape their billions.

The Struengmann brothers’ agreement Monday to lead the purchase of a hand-sanitizer maker owned by EQT AB alongside other investors marks at least the sixth major deal involving the billionaire twins and the Swedish private equity firm within the past decade, according to data compiled by Bloomberg.

The deal for EQT’s Schuelke & Mayr GmbH values the Norderstedt, Germany-based company at about €1.4 billion ($1.5 billion), people with knowledge of the matter have said, asking not to be identified discussing confidential information. Financial details weren’t disclosed. The sale is expected to close in the final quarter of 2023, according to a news release Monday.

A representative for the Struengmanns didn’t respond to a request for comment. The 73-year-old brothers are together worth about $24 billion, according to the Bloomberg Billionaires Index.

A representative for EQT declined to comment on its relationship with the Struengmanns.

The move underscores how private equity firms are aligning themselves more frequently with super-rich families on buyout deals and other opportunities as the companies look beyond their traditional client base such as pension funds and endowments for sources of capital amid a difficult fundraising environment.

Apollo Global Management Inc. is targeting more co-investments with family offices. Blackstone Inc. and KKR & Co. are also building units to focus on wealthy individuals and their investment firms, while many family offices are looking to take advantage of recent market volatility from the shifting macroeconomic and geopolitical landscape.

EQT Bets

Before the Schuelke deal, the Struengmanns most recently dealt with EQT in December to buy a stake from the private equity firm in SHL Medical, a Swiss provider of drug-delivery solutions.

In addition, they invested with EQT for the 2019 purchase of Nestle SA’s skin-health unit, valuing it at 10.2 billion Swiss francs ($11.7 billion), along with a similar deal two years earlier for US biotechnology firm Certara Inc. The brothers also teamed up with EQT during 2014 to buy Siemens AG’s hearing-aid division in one of their first disclosed bets alongside the buyout firm, which has been active in the Struengmanns’ native Germany for more than two decades. They partnered again last year to boost their hearing-aids bet.

“In our conversations with family offices, what comes up time and time again is the importance of having aligned values,” said Per Franzen, head of private capital and deputy managing partner of EQT. “Highly respected and successful family offices see countless investment opportunities day in and day out, so the ‘why’ we do what we do is as important as, if not more, than the ‘what’ or the ‘how.’”

The Struengmann brothers became two of the world’s biggest private investors by reallocating proceeds from their family’s generic drug firms, often focusing on the health sector that first made their fortune. They’ve also diversified their wealth into real estate, energy and finance, selling German lender Suedwestbank AG in 2017 for more than double what they paid for it almost two decades ago.

This year, the siblings allocated funds during May to NexWafe, a German solar wafer producer that also counts divisions of Mukesh Ambani’s Reliance Industries Limited and Saudi Aramco as investors.

They manage their fortune through their family office, Athos, which oversees the brothers’ roughly $10 billion combined stake in BioNTech SE, the German firm that developed a Covid-19 vaccine with Pfizer Inc. The brothers helped to give the drugmaker €150 million in 2008, three years after Novartis AG announced it was buying the brothers’ drugmaker, Hexal.

Thomas Struengmann said in a rare interview with German newspaper Handelsblatt in 2019 that the brothers initially promised themselves they wouldn’t invest more than €1 billion in the biotech sector after selling Hexal because of the risks and requisite patience. They ended up exceeding that cap after seeing glimpses of promise.

“You want to see your little plants continue to grow,” he said.