May 6 (Reuters) - Williams Companies beat first-quarter profit estimates on Monday, as the pipeline operator benefited from increased rates and favorable contributions from acquisitions.

Shares up 1.3% at $39.58 in aftermarket trade.

Tulsa, Oklahoma-based Williams said its Transmission & Gulf of Mexico unit benefited from contributions from the Gulf Coast Storage and MountainWest acquisitions.

The pipeline operator had said in December it would acquire natural gas storage assets from an affiliate of Hartree Partners LP for $1.95 billion and the MountainWest Pipelines business acquisition from Southwest Gas Holdings for $1.07 billion was announced in 2022.

The company's segment includes Transco, the nation's largest-volume interstate natural gas pipeline system, and Northwest Pipeline, a bi-directional interstate natural gas transmission pipeline and storage system.

Quarterly adjusted core profit from the unit was up about 15% to $839 million from a year earlier.

Earnings were also helped by higher rates in the Northeast G&P segment - which provides wet and dry gas gathering and transportation infrastructure - that posted quarterly adjusted core profit of $504 million, up about 7% from a year earlier.

Williams reported a profit of 59 cents per share for the quarter ended March 31, compared with analysts' average estimate of 48 cents per share, according to LSEG data. (Reporting by Tanay Dhumal in Bengaluru; Editing by Alan Barona)