Japanese firms sitting on more than ¥340 trillion of cash are buying back their own shares at a record rate, while turning a deaf ear to calls from Prime Minister Shinzo Abe to step up spending on wages and investment to support the economy.

In February alone, taking advantage of low prices, Japanese companies from SoftBank to Nissan announced they would buy back a total of $9.3 billion in shares, according to Thomson Reuters data — the highest since November 2010 and a monthly amount surpassed only five times in the last 30 years.

The nation's largest companies are under pressure to boost meager returns for their investors, but the volume of cash funneled back raises doubts over the effectiveness of policies to revive growth with cheap cash, part of the government's Abenomics stimulus program.