Japan outmuscled China to dominate mergers and acquisitions in Asia last year, and with companies in possession of more than $890 billion in cash, the spending spree is likely to continue in 2019.

Japanese companies announced more than 1,000 offshore acquisitions totaling a record $191 billion last year, led by Takeda Pharmaceutical Co.'s blockbuster takeover of Shire PLC, according to data compiled by Bloomberg. The last time Japan overtook China by that measure was in 2012.

Faced with the shrinking population and stagnant economy, Japanese businesses have been increasingly looking overseas as trade tensions depress stock prices and bolster the value of the safe-haven yen.