Warren Buffett stoked hopes of a transformation at the world's biggest generic drugmaker as his Berkshire Hathaway Inc. became a top shareholder weeks after pledging to cut soaring U.S. health-care costs.

Shares of the drugmaker, Israel's troubled Teva Pharmaceutical Industries Ltd., surged the most in two months after Berkshire disclosed it had bought about $350 million worth of stock.

Teva, which has its U.S. headquarters in North Wales, Montgomery County, is working on a turnaround after getting bruised by the recent slump in U.S. generics prices. It supplies one in six copycat medicines used by Americans, and its ability to develop cheaper copies of complex treatments could play a role in an ambitious effort to lower health-care costs announced last month by Berkshire, Amazon.com Inc., and JPMorgan Chase & Co.

"Drug costs continue to escalate, Trump is all over prices, and Teva, along with the rest of the generics industry, is part of the solution," Elliot Wilbur, an analyst at Raymond James & Associates, wrote in a note to clients that sought to describe "the 30,000-foot-view approach that may have led Buffett to Teva."

Teva shares closed on Thursday at $20.81, up 7.66 percent or $1.48. With about 1.9 percent of Teva's U.S.-traded shares, Berkshire became the 10th-biggest shareholder in the world's largest manufacturer of generic medicines.

Teva's bonds jumped on the news. Its 1.3 billion euros ($1.6 billion) of notes due 2023 rose 2.1 cents on the euro to 90.5 cents in the morning, the biggest ever intraday jump, according to Trace bond price data.

Buffett is buying into Teva at the early stages of its own repair. The Israeli drugmaker took on a mountain of loans in 2016 to bulk up its copycat medicines business as profit margins declined in the U.S., the world's most lucrative market for pharmaceutical companies. Worse, rival drugmakers began selling cheaper copies of Copaxone, a blockbuster multiple sclerosis injection, dragging profits of Teva's highest grossing product.

The stock lost nearly half its value in 2016 and the following year again.

Teva's new chief executive officer, Kare Schultz, laid out a vast cost-cutting plan in December, halting dividend payments and eliminating 25 percent of the global workforce. He has repeatedly stated that his biggest priority is to curb the company's $31.4 billion debt pile.

Berkshire hasn't revealed the reasons why it bought Teva shares. But the fact that it staked money supports the view of those who say that Teva "is taking the right steps to execute on a successful turnaround," Citigroup Inc. analyst Liav Abraham wrote in an emailed note to clients.