The billionaire Struengmann family behind Covid-19 vaccine maker BioNTech is in talks to take a stake in German diagnostics firm Munich Leukemia Laboratory (MLL) as it seeks to add investments in the healthcare sector, people close to the matter said.

"We are fundamentally interested in a deeper integration of therapy and diagnostics. That is why we are holding talks with Munich Leukemia Laboratory," a spokesman for the Struengmann family holding Athos said.

"In these discussions, we are examining how our business activities can work together more closely," he said, adding that due to ongoing talks no further details could be disclosed.

People close to the matter said the Struengmann family was in talks to take a minority stake in MLL, whose owners chose the serial healthcare investor over buyout firms like EQT and KKR.

They added that talks have not been finalised and MLL's owners could still opt for an alternative investor.

MLL's owners, led by Torsten Haferlach, are working with Goldman Sachs to find an investor for the company which employs around 200 staff and specialises in leukaemia diagnostics and research, the sources said.

MLL generates annual earnings before interest, tax, depreciation and amortisation of around 40 million euros ($47 million) and its owners asked for a valuation of up to 20 times, people close to the matter have said.

Several private equity firms had studied the dossier and weighed the company's revenue growth against factors such as the regulatory risk of potential price caps and the key-person-risk of MLL potentially facing difficulties should co-founders and managers – Torsten and Claudia Haferlach as well as Wolfgang Kern – decide to leave the company.

The Struengmann family still owns just below half of BioNTech, which has a market capitalisation of $23 billion. Other biotech investments include AiCuris, Ganymed and Nexigen.

MLL was not available for comment, while Goldman Sachs, KKR and EQT declined to comment.