Thursday is reopening day for AMC Entertainment Holdings (AMC 0.77%), as it is begins turning back on the lights in 170 of its U.S. cinemas. All told, the company said, it will have almost 300 of its locations open.

This is the second wave of reopenings for the company, which is the largest movie theater chain in the U.S.; the first was smaller, involving over 100 cinemas. AMC said in a press release the reopenings will continue in phases, and the company plans to have around 400 operational by Sept. 3, the date on which the highly anticipated thriller Tenet is scheduled to be released. AMC owns roughly 600 movie theaters throughout the U.S.

AMC movie theater marquee.

Image source: AMC Entertainment Holdings.

The company is promising that moviegoers will be coming back to theaters that have numerous health-protecting measures in place under its Safe & Clean program. These measures include seat blocking that takes into consideration social distancing principles, extra time between showings that allows for more rigorous cleaning and disinfection, and mandatory mask protocols for both guests and employees.

Safe & Clean was devised with the help of advisors currently and previously on the faculty of Harvard University's School of Public Health, and experts at well-known cleaning products maker Clorox.

"Guests returning to AMC can do so knowing that we've been in constant dialogue with top scientists and experts in public health and cleaning about how best to reopen our theatres in ways that will be responsible and welcoming," CEO Adam Aron said in a statement.

Investors appeared pleased with this news. In late afternoon trading Thursday, AMC stock was up by more than 17%.