ProPublica and Mother Jones today co-published an exhaustive report that alleges IBM has for years disregarded age discrimination laws in an attempt to push out employees over 40 and replace them with younger workers. The company is believed to have laid off around 20,000 US employees over 40 years of age over the past five years, though the actual number is believed to be “almost certainly higher.”

Those employees — some of them let go after careers with IBM that spanned decades — saw their jobs either given to “less-experienced and lower-paid workers” or sent overseas. The damning investigative report is culled from a questionnaire filled out by over 1,100 former IBM employees who shared their experiences, interviews, official company documents, and more.

The cuts coincided with IBM’s transition to a business centered around cloud services and data analytics. Apparently, that shift made IBM feel compelled to reach a “correct seniority mix” and “shift headcount mix towards a greater percentage of early professional hires,” according to presentations that were shown to senior executives at the company — including the VP of human resources.

Former workers say performance reviews suddenly became much harsher with the pivot in business focus. Some felt forced to accept an early retirement package when the alternative was being fired outright. IBM encouraged some of those affected to apply for jobs elsewhere in the company, but ProPublica found internal communications that discouraged managers from rehiring them.

Even when they were brought back on, they were met with lower pay and reduced benefits. Employees had to agree to private arbitration to receive severance, leaving them on their own to prove IBM had wrongly run afoul of age discrimination laws. Many have had difficulties finding suitable new jobs after being axed by IBM. “It’s tough when you’ve worked your whole life,” said Brian Paulson, a senior manager who IBM abruptly laid off after 18 years. “Once you get to a certain age, you don’t hear a word from the places you apply.”

IBM’s statement on the report:

We are proud of our company and our employees’ ability to reinvent themselves era after era, while always complying with the law. Our ability to do this is why we are the only tech company that has not only survived but thrived for more than 100 years.

The entire ProPublica / Mother Jones report is a must-read and a sobering look at a once-dominant tech stalwart. There’s also a separate article detailing how the reporters sourced up with the help of a digital community of former IBMers.