Gray Matter Technologies was a company co-founded by Walter White with his friend Elliott Schwartz. The name came from a combination of the two's last names. Schwartz meaning black in German, combined with White made gray.
At this time, Walt was dating his female lab assistant, Gretchen ("...and the Bag's in the River"). For reasons not yet explained, Walter suddenly left Gretchen during a vacation with her family, leaving her and his research behind ("Peekaboo"). Gretchen eventually went on to marry Elliot instead and Gray Matter became a highly successful company using Walter's research. Walter secretly feels that his work was stolen from him and bitterly blames Elliott and Gretchen for his lot in life.
In 2008 the company was nominated for a Nobel Prize ("...and the Bag's in the River").
After leaving Gretchen, Walt sold his share of the company to Elliott for $5,000. As of 2010, Gray Matter has a net worth of 2.16 billion dollars. ("Buyout")
Walt tells Jesse about the company he and his two friends started, their big dreams, their understanding of the unlimited potential of ideas that hadn’t yet germinated. Then, Walt says, “something happened… I’m not going to go into detail…for personal reasons” he took a buyout of his third of the business for $5,000. Now, Walt explains, the company is worth $2.16 billion. He checks the valuation every week, torturing himself about how cheaply he sold his “potential” and his "kids’ birthright.”
Gray Matter is a large reason why, when Walt is given the opportunity to sell his share of the methylamine to a competitor and receive $5 million, he refuses to take the money and leave the meth business. Many reasons for this include Walt's insatiable lust for power, the hubris of believing he’s smart enough to be untouchable, a disdain for anyone presuming to dictate the terms of his life. However, Walt has never gotten over the fact that he co-founded Gray Matter (now worth billions) as a young scientist and then left it. His need for recognition overpowers his more sympathetic drive to set his family up financially. As he tells Jesse of his deal with Declan: “You asked me if I was in the meth business or the money business. Neither. I’m in the empire business.”
Walter believes what he has—not just the physical resources of supplies and equipment he possesses, but more fundamentally, his native resources of intelligence and invention—is of infinite and absolute worth. He feels that he is not going to stop until he’s been fairly compensated for them, which means he’s never going to stop.