T-Mobile (NASDAQ:TMUS) announced earlier this week that it will hold a secondary offering of up to 72 million shares so it can raise additional capital to buy network spectrum. The company is looking for ways to beef up its network, and it hopes the sale of the shares will raise about $1.9 billion.

Connecting to the future
Mobile carriers pay for additional airwaves in order to handle ever-growing Internet usage from mobile devices, and in January the U.S. government will auction off new spectrum to wireless carriers. But Bloomberg has reported T-Mobile won't take part in the auction.

Instead, the company is in the middle of a private deal to buy additional spectrum. T-Mobile has yet to disclose any of the details, or which company it's working with on the deal, but it would likely use some of the money from the stock offering to pay for spectrum if such a deal went through.

Leaving investors a bit anxious
The very brief press release T-Mobile issued after the market closed on Monday has made investors a bit uneasy -- and rightly so. Offering an additional 66 million to 72 million shares will dilute the value of current shares. A Reuters article said that Deutsche Telekom's ownership of T-Mobile will drop from 74% to 67%, even though it's not selling any of its shares.

It's also unclear from whom T-Mobile may be buying the spectrum, how much spectrum it's purchasing, or the potential cost.

That may be asking a lot from investors who just saw the company's average revenue per user drop $1.40 in the third quarter to $52.40. T-Mobile also experienced a net loss of $36 million and spent about $1.2 billion to gain new customers and expand its network this past quarter.

T-Mobile is fighting the larger U.S. carriers and is spending lots of money trying to keep up. The company reached its LTE expansion goal and its network now covers 254 cities and 203 million people, but it has to do more than just expand its network -- it needs to increase the number of customers and average revenue per user. The company has implemented a few strategies to lure customers away from competitors, including payment plans for smartphones, free tablet data, and free international data and texting. Beefing up its network with additional spectrum may be another way to bring in customers, but investors may have to foot the bill with their diluted shares. With its stock up 40% since the beginning of the year, maybe T-Mobile investors will be willing to let this one slide... but I doubt it.