JPMorgan Chase & Co. will soon begin construction on a 12-story office tower as part of the company's expansion of its massive office campus in Plano's Legacy West development.

The banking and financial services giant plans to start construction in the coming weeks on the new tower, which will be the campus's tallest building yet when it's completed in 2021, company spokesman Greg Hassell said. Construction is already underway on a seven-story parking garage, Hassell said.

"This investment is another example of our commitment to the Dallas/Fort Worth market," Hassell said in an email. "We are building for our employees a best-in-class work environment that fosters collaboration and innovation."

The office tower and garage projects are expected to cost nearly $106 million, according to the company's May 29 filing with the Texas Department of Licensing and Regulation.

The project announcements come as JPMorgan Chase prepares to wrap up its first phase of construction in June, Hassell said. The new office tower will house nearly 4,000 employees, and will bring the company's total employees on site to nearly 11,000, he said.

The new parking garage is expected to open by the end of the year.