Japanese companies' cash holdings rose to a record last quarter, highlighting Prime Minister Shinzo Abe's struggle to spur the investment and wage increases needed to end a 15-year deflationary malaise.

Corporate holdings of cash and deposits rose to ¥224 trillion, up 5.9 percent from a year earlier, according to a Bank of Japan report released Thursday.

The yen's 17 percent slide against the dollar this year has boosted exporters' profits, contributing to a cash pile similar in size to Russia's gross domestic product. As Abe campaigns to reflate the world's third-biggest economy, he's relying on company spending to drive a longer-term recovery once the jolt from the unprecedented fiscal and monetary stimulus wears off.