A drag-along right lets a specified majority of shareholders, on approving a sale of the company, compel the remaining holders to sell on the same terms. Its purpose is to keep an exit executable: a buyer usually wants 100% of the company, and without a drag a small minority could refuse to sell and block or extract a premium on a deal the majority wants. The clause “drags” the minority into the approved transaction.
The mechanics that matter are the trigger and the protections. The trigger defines whose approval activates the drag: often a majority of the preferred, or of the preferred and common voting together, sometimes with board and a threshold of common. A founder should know exactly what coalition can trigger it, because it determines who can force a sale. The protections for the dragged holders are the other half: they should receive the same price and form of consideration as the approving majority, should not be asked to give representations or indemnities beyond their own shares, and ideally have their liability capped at their proceeds. A drag without these protections can force minority holders into a deal on worse effective terms.
For founders the drag-along intersects with the liquidation-preference stack in a way that can sting. Because preferences pay out first, a sale that satisfies a deep preference stack can leave little for common, and a drag can compel the founders and employees to accept exactly that outcome. This is why the exit math should be modelled when the clause is negotiated, not at the exit: a reasonable drag (clear trigger, equal terms, capped liability) is standard and healthy, but its interaction with preferences determines what the people building the company actually receive when the drag is finally pulled.