T-Mobile has a current market value of $54 billion compared with Sprint's $32 billion, according to FactSet. Given the size of the companies a merger between the two wireless carriers would be the largest deal of the year.
Johnson & Johnson's $31.4 billion acquisition of Actelion in January was the biggest deal so far in 2017, according to Dealogic data.
"The TMT [tech media telecom] sector has been one of the hottest sectors in the last few years, and if a T-Mobile-Sprint merger goes ahead, it would push deal volume in this sector this year to levels not seen since before the financial crisis," Dealogic's head of Americas M&A research, Agnieszka Zalecka, wrote in an email. "The deal will face huge regulatory scrutiny, and previous talks for Sprint to buy T-Mobile fell through in 2014 because of regulatory concerns."
As mentioned, Sprint was forced to abandon its attempt to acquire T-Mobile three years ago. However, the companies may believe large telecom consolidation is possible under the President Donald Trump administration.
Deutsche Telekom CEO Tim Hoettges also hinted Thursday, he is open to a T-Mobile deal.
"Purely theoretically, we can see several advantages to consolidation and convergence," Hoettges said according to a Reuters report. "The strong position we have established for ourselves gives us the time and space to evaluate all options together with colleagues in the U.S."
If the merger talks get serious, other companies may decide to jump into the fray. Bloomberg News reported in April that Sprint thinks it may get acquisition interest from cable companies such as Comcast, Charter and Altice.
Sprint shares closed up 1 percent on Friday, while T-Mobile stock closed down slightly negative. Both companies did not immediately return requests for comment.
Disclosure: Comcast is the owner of NBCUniversal, the parent company of CNBC and CNBC.com.
Watch: CEO Legere on deal chatter