The 38-year-old reveals the reason behind her shock exit in her new book, Lessons: My Path to a Meaningful Life, as per the Daily Mail.
"For the first five years, I felt comfortable modelling in lingerie, but as time went on, I felt less and less at ease being photographed walking the runway wearing just a bikini or a thong," she writes.
"I was certainly grateful for the opportunity and the financial security the company had given me, but I was at a different place in my life, and I wasn't sure I wanted to continue working there."
But when it came to making her final decision, bizarrely, Bündchen left her fate to chance.
"I crumpled up two small pieces of paper and placed them inside an empty teacup. I closed my eyes and set an intention: whatever piece of paper I chose would be for my highest and best self and be the right decision."
As we now know, the piece of paper she picked up said no.
"'No' was the answer I unconsciously wanted to hear," she explains in her book. "It was also the answer my body wanted to hear, and I believe, had been trying to tell me for days."
One of the world’s highest-paid supermodels, Bündchen signed with Victoria’s Secret when she was 19 years old, Cosmopolitan reports, and continued with them until 2006.