(Bloomberg) -- Vodafone Group Plc and Three UK are putting the final touches on a deal to create Britain’s largest mobile operator and may announce details of the tie-up as soon as this month, people with knowledge of the matter said. 

London-listed Vodafone and Three UK’s owner, CK Hutchison Holdings Ltd., are working through the last details of the structure of the deal, and ways to address potential antitrust issues surrounding it, the people said. 

The companies are also discussing how CK Hutchison may exit its investment in the joint venture in the longer term, according to the people, who asked not to be identified discussing confidential information. 

Analysts have estimated a deal could create a wireless giant worth about €16.5 billion ($17.5 billion). Shares in Vodafone rose as much as 1.7% on Friday. The stock was up 0.4% at 11:17 a.m. in London, giving the company a market value of £26.8 billion ($32 billion). CK Hutchison was down 2% in Hong Kong.

Talks are ongoing and no final decisions on the structure of the merger or timing of any announcement have been made, the people said. Spokespeople for CK Hutchison, Three UK and Vodafone declined to comment. 

Vodafone and CK Hutchison confirmed in October that they were in discussions about merging their UK businesses. Under proposed terms disclosed at the time, Vodafone would own 51% of the new venture, with the rest held by CK Hutchison. Discussions have been held up by a raft of regulatory and political hurdles, as well as the departure of Nick Read as Vodafone’s chief executive officer at the end of 2022. Margherita Della Valle is serving as interim CEO of the British carrier. 

“If the deal can be announced, we would see this as lifting a significant degree of uncertainty as to how much flexibility Margherita has in her role as interim CEO to push through significant portfolio transactions,” New Street Research’s James Ratzer wrote in a note on Thursday. 

A potential deal between Vodafone and Three UK has been talked about for years, and Vodafone previously teamed up with CK Hutchison in other markets such as Australia. Executives believe combining operations in the UK will give the companies the necessary scale to accelerate the roll out of 5G and better compete against the likes of BT Group Plc and Virgin Media O2—both of which struck mergers in recent years.

In his note, Ratzer wrote that any announcement of a deal would likely “be the start of a long journey” to get regulatory approval that could take as many as 18 months and involve the UK’s Competition and Markets Authority.

“A combination of the two would lead to combined 31% mobile subscriber market share,” Ratzer wrote. “We believe therefore this would trigger a lengthy review by the CMA.”

(Updates with shares, analyst comments from fourth paragraph.)

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