BERLIN (Reuters) - German dialysis specialist Fresenius Medical Care is selling its majority shareholding in Sound Inpatient Physicians Holdings for $2.15 billion, it said on Saturday.

The sale to an investment consortium led by private equity firm Summit Partners is expected to close in late 2018 and will bring a pretax book gain of about 800 million euros (£702 million) for the German company.

Fresenius Medical Care, which says it is the world's largest provider of dialysis products and services, bought the stake in Sound Inpatient for about $600 million in 2014 as part of a drive to offer additional services linked to kidney dialysis.

Sound Inpatient provides services such as emergency medicine and critical care. FMC said the investment had enabled it to gain insight in value-based care programmes in the U.S. and that it was now in a position where it could divest Sound Inpatient and use the proceeds for other investments.

In 2017, Sound generated revenues of around 1.25 billion euros and EBIT of around 90 million euros with 3,500 employees.

FMC's financial targets for 2018 and 2020 do not include the effects of the Sound Inpatient sale or the acquisition of NxStage Medical, it added.

FMC is due to publish first quarter results on May 3.

(The story is refiled to remove "euros" from lead.)

(Reporting by Victoria Bryan; Editing by Alexander Smith)