Nearly a dozen billion-dollar deals were announced over the past week, ranging from homebuilders and retail buys to the privatization of a U.S.-listed Chinese technology company. At the same time, Am Law 100 firms had to look no further than the active pharmaceutical arena to add a few notable M&A engagements to their transactional ledger.

Qihoo 360 Technology Co./CEO-led consortium

Beijing-based Qihoo 360, a mobile security software maker, has received a $9 billion buyout offer. The company's chairman and CEO, Zhou Hongyi, is being backed by a consortium of investors—including CITIC Securities Co. Ltd., Golden Brick Capital Private Equity Fund I LP, China Renaissance Holdings Ltd. and Sequoia Capital China I LP—in his bid.