The U.K.’s Competition and Markets Authority on Friday said Vodafone’s proposed merger with rival CK Hutchison will face an in-depth probe, unless the two mobile operators provide “meaningful solutions” to the regulator’s concerns.

Vodafone and CK Hutchison‘s British brand Three have five working days to supply their answers.

The CMA opened a probe into the proposed tie-up back in January. In its latest update Friday, the CMA said it was concerned the deal would lead to a substantial lessening of competition, result in higher prices for consumers and create an unfavorable environment for mobile virtual network operators.

Mobile virtual network operators, or MVNOs, are a spate of new network operators that have cropped up over the years that use underlying infrastructure from existing telcos, rather than being created from scratch.

Announced last year, Vodafone and CK Hutchison’s transaction would merge the two brands’ U.K. businesses, giving Vodafone a 51% controlling stake and leaving CK Hutchison with the minority interest. Vodafone UK CEO Ahmed Essam was set to helm the new enterprise, with Three UK Chief Financial Officer Darren Purkis slated for the CFO position.

The CMA on Friday said that the deal proposed by Vodafone and CK Hutchison could lead to higher prices and reduced quality for U.K. mobile customers. Vodafone and Three are two of the four biggest network providers in Britain and offer important alternatives for consumers, the CMA said.

Three is generally the cheapest of the U.K.’s big four mobile networks, the CMA noted, and combining it with Vodafone could “reduce rivalry between mobile operators to win new customers.”

The CMA also flagged it was worried the deal could make it more difficult for MVNOs such as Sky Mobile, Lebara and Lyca Mobile to negotiate good deals for their customers. Both Vodafone and Three are used by notable MVNOs.

Lebara and Asda Mobile use Vodafone, while Superdrug Mobile is among the MVNOs that uses Three.

Vodafone and Three said that the CMA’s announcement that it intends to refer the firm’s deal with Three for an in-depth Phase 2 review was an “expected next step in the process and in line with the timeframe for completion that we set out from the outset.”

In a joint statement, the two companies said they remain confident that the transaction will deliver benefits for competition, customers and the U.K.

They noted that the quality of mobile network services in the U.K. lags significantly behind other European countries, and that their networks are “sub-scale, unable to cover their cost of capital, and constrained in their ability to invest and compete effectively” against market leaders EE and Virgin Media O2 (VMO2).

Vodafone’s Essam on Friday said that the deal would “create an operator with the scale required to take on BTEE — referencing BT and its mobile brand EE — and VMO2, give MVNOs greater choice in the wholesale market and is in the wider interests of customers, competition and the country.”

Robert Finnegan, CEO of Three U.K., said that the current market structure is “holding the U.K. back, which is not good for customers or competition.”

“By creating a third player with the necessary scale to invest, the combination of our two companies will deliver one of Europe’s most advanced networks and move the U.K. into the digital fast lane, benefiting customers from day one,” Finnegan said.

Schott Pharma debuted on the Frankfurt stock exchange on Thursday at 30 euros per share, trading well above analyst expectations. Shares of the company were up 10% in the first minutes.

The medical vial manufacturer set its final offer price at 27 euros ($28.37) per share Wednesday, after the company announced a range of between 24.50 and 28.50 euros on Sept. 18, giving it a valuation of up to 4.1 billion euros.

The company said it would list 34,641,362 shares in total, including over-allotments.

“We are beyond thrilled about today’s milestone. There is strong demand not only for our leading drug containment solutions and delivery systems but also from investors worldwide, proving the great prospects of our company,” Andreas Reisse, CEO of Schott Pharma, said after the offer price announcement of Wednesday.

Schott Pharma said sales were up 8.4% year-on-year for the first nine months of the 2023 fiscal year, hitting 670 million euros ($704 million) over the period.

The company produces vials for mRNA vaccines, diabetes and obesity drugs and counts BioNTech and Moderna among its clients. Schott Pharma has production and sales units across 33 countries.

The group said it will retain a majority stake in the company following the completion of the IPO and plans to use money raised through the listing to “further accelerate the Group’s growth and support its green transition.”

The Schott Pharma IPO is only the third new listing on the Frankfurt stock exchange this year and is expected to be the largest.

Microsoft says it “really tried” to take the concerns of U.K. regulators to heart, before launching its fresh bid to take over Activision Blizzard — and it’s now up to the regulators to decide whether that path is clear.

“I think we need to let the regulators speak for themselves,” Microsoft’s vice-chairman and president Brad Smith told CNBC in an exclusive interview. “They have decisions that need to be made, especially in the U.K., but from my vantage point, what we’ve really tried to do is take these concerns to heart.”

Last Tuesday, Microsoft submitted a new proposal to U.K. regulators for the takeover of American game publisher Activision Blizzard after its initial proposal was rejected.

Microsoft and Activision have agreed to a new, restructured agreement, which the U.K.’s Competition and Markets Authority will now investigate with a decision deadline of Oct. 18.

On regulatory concerns, Smith said: “We haven’t tried to dismiss them. We haven’t tried to downplay them. We haven’t tried to ignore them.”

“We’ve worked to address them, and by addressing them, we have put together a transaction that will advance competition, while also eliminating the concerns on the anti-competitive side that some people had,” he told CNBC’s Martin Soong on the sidelines of the Business 20 Summit in New Delhi.

“I think it will be up to the regulators, especially now in the U.K., to decide whether that path is clear,” he said in an interview aired Monday.

U.K. regulators, the Competition and Markets Authority, said that under the new deal, Microsoft will not acquire cloud rights for existing Activision PC and console games, or for new games released by Activision for the next 15 years.

Instead, French gaming publisher Ubisoft will acquire those rights before Microsoft’s acquisition of Activision, the CMA added.

“That to me, is not just a recipe for this transaction,” said Smith.

“I think that in the world of technology, whether we’re talking about software or hardware or pharmaceuticals, there are times when companies can come together in advance innovation, produce better products, and there may be steps that need to be taken at the same time to address regulatory concerns.”