Warren Buffett's Berkshire Hathaway reported larger holdings of the Israeli pharmaceutical company Teva Pharmaceutical for the first quarter. The conglomerate also increased its stake on St. Louis-based agricultural product giant Monsanto.

Berkshire more than doubled its stake in Teva, to 40 million shares, in the first three months of this year after first reporting a stake of 18.8 million shares in the fourth quarter of last year. The changes are reflected in Berkshire's latest regulatory filing on Tuesday, but they only report holdings up to the end of March.

Shares of Teva rose 3.3 percent in premarket trading Wednesday.