what is protection from "pump and dump" here? He isn't allowed to dump the stock for some time? doesn't seem so. One reason Buffet, for example, has special reporting arrangement with SEC is to prevent such volatility, and as a side effect i think it also decreases potential for such pump and dump on his side (not that i imply that Buffet would succumb to such temptation :)

edit: after refreshing myself on Buffet's exception, it seems it protects his interests from volatility, not public's :).