By Dave Sebastian

Liberty Oilfield Services Inc. is combining with OneStim, Schlumberger Ltd.'s pressure-pumping business in North America, a transaction in which Schlumberger will get 37% of the combined entity's equity.

The deal is expected to close in the fourth quarter, the companies said Tuesday. Liberty's current management team will continue leading the company.

The companies said the combined entity has 2019 pro-forma revenue of $5.2 billion and pro-forma market capitalization of $1.2 billion.

Schlumberger shares rose 1.3% in premarket trading, while Liberty shares were flat.

Write to Dave Sebastian at dave.sebastian@wsj.com