Staples said Wednesday that it would buy its competitor in the office-supplies market Office Depot in deal worth about $6 billion.

According to USAToday reports, the acquisition is a cash-and-stock deal that will see Office Depot's shareholders receive $7.25 in cash and 0.2188 of a share in Staples. The deal values Office Depot at $11 per share as of Feb. 2. That's 44% more than the firm's share price closed that day.

The companies put the transaction's value at $6.3 billion. Together, the firms will have annual sales of approximately $39 billion.

"This is a transformational acquisition which enables Staples to provide more value to customers, and more effectively compete in a rapidly evolving competitive environment," said Ron Sargent, chairman and chief executive officer of Staples.

The deal, which was approved unanimously by both companies' board of directors, is expected to close by year's end.

Staples' pre-market shares fell about 1 percent on Wednesday to $18.80.