Sullivan & Cromwell, Linklaters and Simpson Thacher & Bartlett have picked up mandates on the $5.9 billion hostile takeover bid launched earlier this week by German pharmaceuticals giant Merck for U.S. chemicals manufacturer Versum Materials.

The offer comes a month after U.S. manufacturer Entegris previously proposed to merge with Versum Materials to create a combined company with a market valuation of about $9 billion, according to Entegris.