In the biggest acquisition in the history of the family-owned company, Darmstadt Germany-based chemicals, pharmaceuticals and laboratory products manufacturer Merck KGaA is opening its well-filled war chest to buy US-specialty life science company Sigma-Aldrich for $17 billion in cash.

The $140 per share offer unveiled on Sept. 22 represents a 37% premium on the Sept. 19 closing price of the St Louis, Missouri firm, which has annual sales of $2.7 billion and claims to be the world's largest supplier of biochemical and organic chemicals to research laboratories.

Buying Sigma-Aldrich - the transaction is expected to be completed in mid-2015 - will expand the portfolio of Merck's laboratory supply subsidiary Merck Millipore in North America and give it an enhanced presence in Asia.

Describing the deal as a "quantum leap" for Merck, CEO Karl-Ludwig Kley said that by offering a much broader product slate, the merged companies would be able to secure stable growth and profitability in an industry driven by globalization trends.

Merck expects synergies of around €260 million ($334 million) within three years after closing.

CFO Marcus Kuhnert said savings would come in part from combining manufacturing capacity and streamlining administrative functions. The portfolio is said to be complementary along the entire vale chain of drug production and validation. No information on possible job losses or site closures has been announced.

Sigma Aldrich currently has more than 9,000 employees in 40 countries. Its president and CEO, Rakesh Sachdev, called the takeover offer "a clear validation" of its successful transformation into a customer-focused and solution -oriented global organization."

Both Sigma-Aldrich's board of directors and Merck's board of partners have signalled their approval.

Kley said Merck has secured bridge financing for the cash deal and expects that the final financing structure to be comprised of a combination of cash, bank loans and bonds.

The German company acquired US-based Merck Millipore in 2006 for $6 billion, the same year it bought Swiss biopharmaceuticals producer Serono for €10.3 billion ($ 13.3 billion).