Barbara L. Borden

At this stage in her career, Borden feels like she's earned a degree in psychology. As the co-chair of Cooley LLP's mergers and acquisitions practice, she's dealt with her share of personalities when closing big transactions.

"It's about trying to get parties to agree to stuff and bridge gaps when people have different perspectives," she said. "You don't have to win every point. You have to pick and choose your battles."

In the past year, Borden advised on a variety of multibillion-dollar deals at Cooley with a particular focus on life sciences and tech. In February, she finalized the sale of Cooley client Zeltiq Aesthetics Inc., a medical device company, to Allergan PLC for $2.475 billion. She also helped Horizon Pharma PLC and DraftKings Inc. finalize deals with Raptor Pharmaceutical Corp. and FanDuel Inc., respectively.

In spite of these success stories, Borden said she's witnessed more deals falling apart in recent years.

"The M&A market goes up and down," she said. "I think over time that people have become more disciplined and are willing to walk away from deals if they're just not coming together."

Borden has been able to maintain a constant string of successes thanks to her pragmatic approach.

Allergan, for example, walked away from the Zeltiq deal twice before Borden and her team solidified the sale this year.

"My client doesn't always have the superior leverage and, even if they do, they want an outcome both sides see as a good outcome," she said. "So rather than scoring points for the sake of it, I try to be pragmatic about what's important."

— Paula Lehman-Ewing