Allied Properties Real Estate Investment Trust and RioCan Real Estate Investment Trust’s new office development in the heart of Toronto’s technology district has a core tenant: Index Exchange Inc., the closely held global advertising marketplace.

The Toronto-based firm will lease as much as 200,000 square feet (18,600 square meters) at Allied and RioCan’s The Well, the companies said Tuesday in a statement. Index Exchange agreed to a 12-year lease starting in 2022. The development includes more than 1 million square feet of downtown office space.

Toronto’s office-market growth is driven by a surge in tech that accounted for more than a third of the downtown demand last year, according to CBRE Group Inc. The city was the fastest-growing tech-employment market in 2017, with more new jobs created than in the San Francisco Bay Area, Seattle and Washington, D.C., combined. Global advertising and marketing giant WPP Plc announced on Friday that it would be the anchor tenant at a new development on Toronto’s east end.

“It has been a pretty exhaustive search,” Index Exchange Chief Executive Officer Andrew Casale said by phone. “There is also already a talent war. That war is only going to intensify as we go forward we wanted a property that would be a draw for talent as we go ahead.”

Read more: Allied eyes bond to fund office push for Toronto tech

Index Exchange plans to consolidate four regional offices into the new space. The company, which has about 440 employees globally, expects to grow to about 1,000 in Toronto alone by 2022. Index Exchange, founded in 2001, is an automated marketplace used by digital media companies to sell ad space to buyers. Clients include Bloomberg LP, the parent company of Bloomberg News, as well as CBS Interactive.

“We’re growing really fast, we’re super optimistic that we could grow even faster,” Casale said. “In the past three years, we have doubled the company each consecutive year.”

Allied and RioCan said that another tenant has agreed to lease 125,000 square feet at The Well. They didn’t name the tenant. Two deals for more than 500,000 square feet are being negotiated, which could bring total leased commitments for the project to 80 percent.

The companies each own 50 percent interest in the commercial part of The Well, which also includes residential and retail components. The development is to include about 1.5 million square feet of residential space spanning six buildings, and about 1,800 residences.

Source: Bloomberg