Fresenius SE & Co KGaA (FSNUY) was one of the top gainers on Germany's DAX Tuesday after it announced a deal to buy U.S. generic drugmaker Akorn Inc (AKRX - Get Report) for $4.75 billion and the biosimilars unit of German rival Merck KGaA (MKGAY) .

Fresenius stock was up 0.47% by noon CET to change hands at €75.70, extending a three-month gain of 3.15%. Germany's Merck leaped to the top of the DAX, gaining 2.82% to €107.45. Shares are up more than 5% over the past three months.

Fresenius late Monday said its Fresenius Kabi unit, which focuses on products for chronically and critically ill patients, had diversified its product portfolio with the Akorn and Merck purchases.

The German company offered $34 per share for Akorn, valuing the deal at $4.3 billion plus approximately $450 million of net debt.

Akorn produces and markets a diverse product portfolio of injectables, topical creams, ointments and gels, sterile ophthalmics, as well as oral liquids, otic solutions (for the ear), nasal sprays and respiratory drugs. Akorn products are sold in retail pharmacies (prescription and over-the-counter) and directly to physicians, in addition to hospitals and clinics - almost exclusively in the U.S.

Akorn Monday reaffirmed 2017 guidance of revenue of $1.010 billion to $1.060 billion and adjusted EBITDA of $363 million to $401 million.

Fresenius Kabi will also acquire Merck's biosimilars business, which comprises the entire development pipeline and an experienced team of more than 70 employees. The product pipeline has a focus on oncology and autoimmune diseases.

The purchase price will be up to €670 million comprised of €170 million to be paid in cash upon closing and approximately €500 million in milestone payments strictly tied to achievements of development targets.

Both deals are subject to regulatory approvals.