Passage: Although calm was largely restored in New York by Saturday, November 2, yet another crisis loomed. One of the exchange's largest brokerage firms, Moore & Schley, was heavily in debt and in danger of collapse. The firm had borrowed heavily, using shares of the Tennessee Coal, Iron and Railroad Company (TC&I) as collateral. With the value of the thinly traded stock under pressure, many banks would likely call the loans of Moore & Schley on Monday and force an en masse liquidation of the firm's stock. If that occurred it would send  TC&I shares plummeting, devastating Moore and Schley and triggering further panic in the market.To avert the collapse of Moore & Schley, Morgan called an emergency conference at his library Saturday morning. A proposal was made that the U.S. Steel Corporation, a company Morgan had helped form through the merger of the steel companies of Andrew Carnegie and Elbert Gary, would acquire TC&I. This would effectively save Moore & Schley and avert the crisis. The executives and board of U.S. Steel studied the situation and offered to either loan Moore & Schley $5 million, or buy TC&I for $90 a share. By 7 p.m. an agreement had not been reached and the meeting adjourned.By then, Morgan was drawn into another situation. There was deep concern that the Trust Company of America and the Lincoln Trust might fail to open on Monday due to continuing runs by depositors. On Saturday evening 40–50 bankers gathered at the library to discuss the crisis, with the clearing-house bank presidents in the East room and the trust company executives in the West room. Morgan and those dealing with the Moore & Schley situation moved to the librarian's office. There Morgan told his counselors that he would agree to help shore up Moore & Schley only if the trust companies would work together to bail out their weakest brethren. The discussion among the bankers continued late into Saturday night but without much progress. Around midnight, J. P. Morgan informed a leader of the trust company presidents that keeping...

Question: What companies shares did the firm used as collateral for what they borrowed?
Tennessee Coal, Iron and Railroad Company (TC&I)