Britain’s competition watchdog said on Nov. 22 that U.S.-listed oilfield services firm Baker Hughes Co.’s acquisition of Altus Intervention could reduce competition among U.K. oil and gas operators.

The Competition and Markets Authority (CMA) said it was concerned that the loss of rivalry between the merging companies could lead to higher prices, reduced choice and lower quality services for businesses in the U.K. that purchase coiled tubing and pumping services.

In the U.K., both Baker Hughes and Altus supply various well intervention services—essential services used by oil and gas operators to manage well production.

Baker Hughes said it was reviewing the regulator’s findings and would work constructively with the CMA.

The U.S. company added that the regulator had not questioned the deal rationale but only highlighted overlapping businesses in the areas of coil tubing and pumping services in the UK.

Altus did not immediately respond to a Reuters request for comment.

The CMA said its Phase 1 investigation found that Baker Hughes would face competition from only one major supplier—Halliburton—after the deal between the two largest providers of both coiled tubing and pumping services in the U.K.

The regulator said Baker Hughes and Altus have five working days to submit proposals to address its concerns, otherwise the watchdog will refer the deal to an in-depth Phase 2 probe.