Superseding it in recent years has been publicly traded Waitrose, a high-end chain that worked to broaden its supply of organic produce and certify the origin of products bought internationally. Also helping to bring RC fully out of its niche was Sainsbury's, one of the four big mainstream chains. Sainsbury's saw an opportunity to differentiate itself as the "supermarket with a conscience," and it has invested heavily in a variety of areas, most notably fair trade.