(from instructions)
"Megamerger is a game where industrial empires are built through strategy and finesse, by merging single industries into powerful conglomerates. Players acquire control of selected industries, collecting higher fees as their empires become more powerful. Along the "Road to Riches" they find greater challenge as opponents build competing conglomerates and as each one formulates strategies for financial supremacy."
In MegaMerger players move around the board buying up shares in various industries. They can own anywhere from 5% of an industry, up to 100% in an industry. Players want to control many industries in the same color in order to make a "conglomerate" which will help them expand how much money they get from players who land on their industries.
However, just because a player owns a part of an industry does not prevent it from being bought by another player. Unlike Monopoly, as long as the player has something, they are in the game. This could be as little as 5% ownership in an industry with no money in front of them.