Amazon (AMZN) has kicked up its investment in its Chicago Tech Hub and will create 400 new tech jobs in a variety of fields. The Chicago Tech hub expansion will include an additional 70,000 square feet of office space and double the number of tech jobs for the company in the city.

The e-commerce giant is hiring for jobs in cloud computing, advertising, and business development and will hold a Career Day event on Tuesday. The company will also hold Career Day events in Boston, Dallas, Nashville, Seattle and Arlington, Virginia, this week.

The Career Day event in Chicago will take place at the Vertiport Hangar located at 1339 S. Wood Street in Chicago from 11:30 a.m. to 7 p.m. The company said that recruiters will be on-hand to discuss available job positions at the company’s 18 Tech Hubs as well as jobs within its fulfillment, delivery, and retail facilities.

Amazon will also hold information sessions on how to sell on Amazon, how to become a Delivery Service Partner or publish a book on its site.

Amazon has been recognized as a top employer, offering employees comprehensive healthcare, 401(k) match, up to 20-weeks of paid parental leave, and tuition payment for in-demand job skills.

“We’re excited to create more opportunity in Chicago – a city with terrific talent and a culture of innovation,” Geoff Nyheim, director Central US AWS Sales at Amazon said. “We look forward to doubling our teams in the Windy City, contributing to its diverse economy, and hiring local talent to fill exciting roles across Amazon.”

Amazon has 18 North American Tech Hubs as well as headquarter locations in Seattle and Arlington, Virginia. The hubs employ more than 20,000 workers with the Chicago location responsible for the build and support of products and services for Amazon Web Services, Amazon Advertising, and the retailer’s Transportation and Operations units.

In total, Amazon has 11,000 full-time jobs in Illinois. The company has invested $4.4 billion in the state since 2010.

Shares of Amazon stock were down 2.03 percent as of 12:12 p.m. ET on Monday.