A trawl of 20,000 employee reviews from careers website Glassdoor showed a major decline in staff satisfaction at Shire in 2017, with the company coming 24th out of 26 biopharmaceutical companies on "overall satisfaction", UBS said.

Shire, which recently lost its chief financial officer and head of research, faces testing times after buying United States-based Baxalta in its biggest ever deal, leading to inevitable upheaval and challenges.

In 2015 and 2016 Shire and Baxalta were just below the middle of the pack on most employee satisfaction measures.

"Neither markets nor employees seem as confident as management that things are on track," UBS said, reducing its 12-month price target to 40.95 pounds a share from 45 pounds while rating the stock neutral.

Shire's chief human resources officer, Joanne Cordeiro, said the drugmaker's own surveys painted a more encouraging picture.

"We are in the late stages of significant corporate transformation as we have evolved into the global leader in rare diseases," she said.

"Our internal engagement marks for Shire are high despite these changes. We are focussed on working to ensure we continue to build the best organisation for our employees, patients and shareholders."

(Reporting by Ben Hirschler; Editing by David Goodman)