Office supply giant Staples will be sold to a private equity firm for $6.9 billion as online stores continue to edge traditional retailers out of the market. Sycamore Partners, a private equity firm that owns Talbots, the Limited, and Hot Topic, among other retailers, announced on Wednesday that it was acquiring the “iconic” Staples brand. The move comes at a time when the office supply chain has seen sales and gross profits steadily declining for the past four years. The company acknowledged the challenges faced by its “underperforming” business in an annual report earlier this year, announcing that it would close about 70 stores in North America this year to reduce risks. Stefan Kaluzny, managing director of Sycamore Partners, seemed unfazed, however. Kaluzny said in a statement released Wednesday that the private equity firm hopes to “accelerate long-term profitability” for the Staples brand.