What percent ROI should someone have to be considered a shark

[ssuglia]

What percent ROI should someone have to be considered a shark

ROI % by itself can be inaccurate when judging a player's ability. A player could have one big cash, but a small sample size of tournaments played, which can skew the numbers. A player could also be playing outside of their bankroll/ability, and as a result have stats that look far worse than the person's true ability.

You would need a lot more information beyond ROI to determine whether a player is a shark or not.