LONDON The largest owner of IKEA stores has acquired supply chain software firm Made4Net as the Swedish furniture retailer plans a major expansion in the United States and aims to grow its online sales.

Ingka Group's investment arm Ingka Investments bought the company for an undisclosed sum, the company said, in order to improve IKEA's warehouse and logistics operations as shoppers increasingly demand next-day or same-day delivery.

Made4net's software analyses companies' warehouses, worker productivity, and delivery routes to find efficiency gains and cut costs.

"Our business currently requires a better fulfillment operations system with more accurate data that better supports handling for our customers," said Tolga Oncu, head of IKEA Retail at Ingka Group.

Ingka plans to open eight new big IKEA stores and nine smaller stores in the U.S., as well as upgrading existing stores. The U.S. is IKEA's second-biggest market by sales after Germany.

Under the deal, Made4Net will operate as an independent subsidiary and continue to serve its existing customers, which include H&M, DHL, and Uber.

(Reporting by Helen Reid; Editing by David Gregorio)