Shares in US operator Sprint closed up last week after the firm announced Friday it was to raise an extra US$4 billion in debt, reports Bloomberg. The news eased investor concerns that the operator could struggle to support its LTE and iPhone rollouts, while continuing to prop up its struggling wholesale partner, Clearwire.

Sprint said in a statement Friday that it is issuing US$3 billion of seven-year 9 percent notes and US$1 billion of ten-year, 11.5 percent notes. The sale is expected to be completed on 9 November (Wednesday).

The firm announced last month that its LTE rollout will be complete by the end of 2013, some two years earlier than previously indicated, an upgrade expected to cost at least US$5 billion. It is also expected to pay considerable subsidies to Apple in order to offer the iPhone, which may mean the device does not start having a positive impact on the company’s bottom line until 2015.

Sprint added that proceeds from the notes will also be used “for general corporate purposes, which may include, among other things, redemptions or service requirements of outstanding debt, network expansion and modernisation and potential funding of Clearwire.”

“The fact that funding Clearwire is mentioned as a possible use of proceeds suggests the companies are moving in the right direction,” Jonathan Chaplin, an analyst at Credit Suisse, told Bloomberg.

He added that the debt sale is a positive for Sprint because it shows that the company still has access to capital markets.

Shares in Sprint closed up 2.1 percent on Friday to end the week at US$2.87. Clearwire – whose shares have lost 63 percent this year – gained 8 percent to close at US$1.89.