What is a defining trait of unicorn start-ups?

A defining trait of unicorn start-ups is their rapid valuation growth to one billion dollars. Unicorns are typically private companies that achieve a valuation of over a billion dollars, often within a relatively short time frame after their establishment. This rapid growth is usually fueled by innovative business models, disruptive technology, or significant market demand, positioning them as high-potential investments in the venture capital world.

In contrast, the other options do not accurately capture the essence of what makes a company a unicorn. Stable growth over decades may describe well-established firms but does not reflect the explosive growth typically associated with unicorns. Continuous loss of market interest would indicate declining performance, which is contrary to the success reflected in a unicorn's valuation. Similarly, minimal disruption in existing markets would suggest that a company is not innovating or attracting significant investor interest, which is fundamental to being classified as a unicorn.