Both Uses of

market share
in
Blink, by Malcolm Gladwell

Their client, Christian Brothers, wanted to know why, after years of being the dominant brand in the category, it was losing market share to E & J. Their brandy wasn't more expensive.†
Chpt 5 *

market share = a company's sales in a given industry expressed as a percentage of the sales for the entire industry

Clearly people had more positive associations with the name Christian Brothers than with E & J. That only deepened the mystery, because if Christian Brothers had a stronger brand, why where they losing market share?†
Chpt 5