1. It's worth at minimum, 6 billion to a national carrier.
2. Their income statement and cash flow will look a lot better after they get everybody migrated to LTE. At that point its probably worth 8 billion to a national carrier. Right now the numbers are temporarily crummy...running two technologies at the website, inefficient billing and sales processes, unfortunate need to bribe customers with handset subsidies, generally high overhead. All of those things are either fixable before a sale, or will be fixed by the eventual buyer.
3. Popular stocks are so high that money managers are forced to look elsewhere. This is attractively priced and has the upside on takeover and/or takeover speculation.
4. Interest rates are low. No debt problem here.
5. gravitational pull of Mercury and the color of socks worn by CEO.