San Francisco’s biggest private employer has major expansion plans in Chicago, even as it grows more in its hometown.

Salesforce will pay $475 million over 17 years to rent an office in a deal struck this month, with plans to take occupancy in 2022, the company revealed in a Securities and Exchange Commission filing. While the filing did not state the square footage rented or location of the building, Salesforce chief Marc Benioff said in a tweet Thursday that the company would open Salesforce Tower Chicago in 2023, and a source with direct knowledge of the deal said the building referenced in the filing was in that city.

In an additional indication of Salesforce’s plans, a business partner of the company, Galacticos, posted a tweet Thursday that announced “our newest tower, Salesforce Tower Chicago!” The tweet included a rendering of a riverfront tower in Chicago and a link to a nonworking page on Salesforce’s corporate blog. Galacticos’ Twitter account appears to post links to Salesforce announcements frequently using an automated tool. Benioff’s tweet, posted later, included the same rendering.

Salesforce is still growing in its San Francisco headquarters, where it already has a 8,500-person workforce and plans to reach at least 10,000 employees. The filing revealed it would pay $500 million over 16 years in its Parcel F tower deal in San Francisco. The Chronicle reported this month that Salesforce leased a third of the Transbay tower, which will be the city’s fourth-tallest if it gets the required approvals.

Salesforce did not comment. Benioff and Elizabeth Pinkham, the company’s head of real estate, have spoken about plans to plant Salesforce Towers in other cities where they have significant numbers of workers. Already, Indianapolis, New York and London have such buildings, and a tower in Atlanta will open next year. The edifices are typically high rises and have space for local nonprofits.

The Chicago deal is a massive economic boost for a growing hub for the tech sector where real estate costs half what it does in the Bay Area. In July, Facebook signed a deal for a downtown office building for 2,000 employees, according to the Chicago Tribune. Google expanded its Chicago offices last month.

Bay Area tech companies have vast resources to expand — Salesforce recorded more than $3 billion in revenue in the third quarter — but are competing fiercely at home for both employees and office space, prompting them to consider expansions elsewhere.

Chicago was also a finalist for Amazon’s second headquarters, but ultimately lost out to New York and Northern Virginia. The Bay Area bid for Amazon, which didn’t offer any tax subsidies, wasn’t named as a finalist.

Crain’s Chicago reported in August that Salesforce was in talks for a lease at the Wolf Point South Tower project. A potential deal would reportedly encompass 500,000 square feet, space for around 2,500 to 3,000 employees.

Wolf Point, where three branches of the Chicago River meet, includes a trio of towers: one residential building completed in 2016, one residential tower under construction, and a 950-foot planned office tower. The image in the tweets posted Thursday matches other renderings of the project.

A Salesforce spokeswoman declined to comment. The company has over 100 active job listings in Chicago.

Hines and Joseph P. Kennedy Enterprises are the developers of the Wolf Point South Tower, which requires city approval. Hines is also an owner of Salesforce Tower and Parcel F. The company did not respond to requests for comment.

Salesforce would be working with a familiar architecture firm at Wolf Point: Pelli Clarke Pelli, which also designed Salesforce Tower, the Transbay transit center named after Salesforce, and the future Parcel F tower.

Downtown Chicago Class A office asking rents were $44.68 per square foot in the third quarter, just over half of San Francisco’s record-setting $81.25 per square foot, according to brokerage Cushman & Wakefield.

Housing costs are also vastly lower. Chicago’s average rent is $1,808 per month, just over half of San Francisco’s average of $3,442 per month, according to housing site RentCafe.

The Chicago Tribune reported in September that the city was seeking to loosen its restrictions on signs on buildings. A large Trump sign on Chicago’s second-tallest building caused backlash and led to the restrictions.

Back to Gallery Cloud in the Windy City: Salesforce to spend $475 million... 2 1 of 2 Photo: Steelblue 2 of 2 Photo: Jessica Christian, The Chronicle



“The adjustments will also better accommodate the needs of large anchor tenants, strengthening Chicago’s attractiveness to large companies that create large numbers of jobs. The adjustment would accommodate a Fortune 500 company that will soon create thousands of jobs in Chicago,” Chicago Mayor Rahm Emanuel’s office said in a statement, according to the Tribune.

In San Francisco and around the country, Salesforce places its blue cloud logo on the towers it occupies.

Roland Li is a Chronicle staff writer. Email: roland.li@sfchronicle.com Twitter: @rolandlisf