American companies will become even bigger buyers of bonds sold by their peers as negative interest rates worldwide intensify pressure on them to deploy their $4 trillion cash pile, according to Citigroup Inc.

“In their search for yield, companies are likely to increase their allocation toward one- to five-year corporate bonds rated A or higher,” said Ajay Khorana, global head of Citigroup's financial strategy and solutions group.

During the past two years companies have purchased as much as 15 percent of all new A-rated corporate bonds with a maturity of one to five years, according to Khorana. That's more than pension funds, banks, or insurance companies, as treasurers search for places to invest record amounts of cash at a time when yields are evaporating on safer investments such as Treasuries.