SoftBank is reportedly making another run at T-Mobile - and T-Mobile is up 4%

The Japanese telecom SoftBank, which owns Sprint, is looking to make another run at T-Mobile US, Reuters reports.

T-Mobile's stock is up 4% on the news.

This would be the second time Softbank has made an effort to acquire T-Mobile.

It explored the idea in 2014, only to back down after telecom regulators made it clear they would block any acquisition of the fourth-largest US carrier.

In 2011, AT&T struck a $39 billion deal to acquire T-Mobile, but walked away after US regulators threatened to block it.

More to come...