Reddit, the popular internet forum, will move its headquarters to a new office in San Francisco’s Mid-Market, becoming the latest tech company to arrive in the neighborhood.

The company confirmed it leased space at 1455 Market St., which is also the headquarters of Uber and Square. The lease covers 78,000 square feet, according to real estate data firm CoStar.

Mid-Market has transformed from an undesirable office district to an epicenter of tech growth since 2011, after the city passed a payroll tax break for companies located there. The massive 1455 Market St. building wasn’t included in the tax break, which expired this year, but it benefited from tech momentum in the area, landlord Hudson Pacific Properties previously told The Chronicle.

WeWork also recently opened a co-working space on the ground floor, which was formerly a Bank of America vault.

Reddit is subleasing space on the 16th, 17th and 20th floor from Square, according to two people with direct knowledge of the deal who aren’t authorized to speak publicly. Square didn’t immediately respond to a request for comment.

Reddit, which has 500 employees globally, will leave its current headquarters at 420 Taylor St. near Union Square. The city approved a renovation of 420 Taylor St. to convert a lower level parking garage into office space and create a new lobby with floor-to-ceiling glass, according to marketing materials on CoStar. The entire 115,766-square-foot building is currently being marketed for lease, according to CoStar.

Seven Equity Group, the owner of 420 Taylor St., didn't immediately respond to a request for comment.

The U.S. Army Corps. of Engineers last occupied the space that Reddit leased at 1455 Market. The Army Corps. moved to the Federal Building at 450 Golden Gate Ave. in December, said Brandon Beach, chief of public affairs for the federal agency’s San Francisco division.

Reddit is the sixth-most visited website in the U.S., according to Alexa, an analytics company owned by Amazon. Users submit links to news stories, images and discuss a variety of topics.

Reddit raised $300 million from Chinese tech giant Tencent and other investors in February, at a valuation of $3 billion, according to Techcrunch, which said it had 330 million monthly active users in 2018.

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