Three huge North American investors have piled into the U.K. build-to-rent sector, in a major boost for the burgeoning rented residential market.

Atlanta-based Cortland Partners has bought U.K. developer Orion Land and is planning to invest up to £4B building up a portfolio of 10,000 homes. The deal was first reported by Estates Gazette.

The venture has an initial pipeline of four sites that will total between 1,600 and 2,000 units. Two are in London, one is in Watford and one is in the Midlands. Cortland owns 45,000 units in the U.S. with a range of institutional partners.

In the second deal, Canada Pension Plan Investment Board has formed a joint venture with Australian developer Lendlease to invest £1.5B in the sector. It will back the next stage of Lendlease’s Elephant Park scheme comprising around 600 flats in South London. That scheme will cost £450M, with CPPIB providing £350M.

Finally, Oxford Properties is close to agreeing a deal to buy a stake in Get Living, the private-rented-sector business run by Delancey and whose backers include APG and Qatari Diar. It is also developing a scheme in the Elephant & Castle area as well as Glasgow and Leeds, with its pipeline totalling 6,000 units, Estates Gazette reports. Oxford has said it will invest £1B in the sector.

There are 105,214 build-to-rent units either completed or planned across the U.K., including 19,106 completed, 27,566 under construction and 58,542 with planning permission, according to the British Property Federation. In London, there are a total of 59,271 units and outside London, there are 45,943 units.