The 30-year-old joined the company, led by Claire Powell, last year under strict conditions following her divorce from second husband Mark Croft.
PR guru Powell also manages the careers of Peter Andre, Amy Childs and Nicola McClean.
"For those asking, it is true that Kerry Katona and CAN Associates have parted ways," News of the World journalist Dan Wootton tweeted last night. "Not great news for Kerry, in my opinion."
> Powell: 'Kerry Katona was a lost soul'
> Andre agent Claire Powell opens celeb clinic
Meanwhile, it has been claimed that Can let Katona go after she spent a night out with friends, failing to turn up at The Only Way is Essex star Childs's 21st birthday party.
"We rescued Kerry from obscurity a year ago. We have spent a lot of money cleaning up her image. We have given her a whole new image, new clothes, a new life and she has blown it all," a source close to the company told the Daily Star.
After signing the former Atomic Kitten singer, Powell had warned: "Kerry knows this is her last chance. If she is prepared to work hard and stay clean she has a great career ahead of her."
Katona, who competed in Dancing on Ice earlier this year, previously told Digital Spy that Can bosses Powell and Neville Hendricks were "like the best surrogate parents".
Watch Digital Spy's interview with Kerry Katona from March 2011 below: