Eastman Kodak Co. warned in a regulatory filing that "substantial doubt" exists about its ability to continue as a going concern, citing the absence of committed financing to meet roughly $500 million of debt that falls due within the next 12 months. The Rochester, New York-based company ended the second quarter with $155 million in cash and equivalents, reported a net loss of $26 million on revenue of $263 million, and said rising costs and lower profitability had drained $46 million of cash since December. The disclosure sent Kodak’s shares tumbling about 25 percent in New York trading. Chief Financial Officer David Bullwinkle said Kodak intends to use an expected $300 million cash inflow from the planned reversion of its U.S. pension plan and to refinance, amend or extend the remaining obligations. Executive Chairman and Chief Executive Officer Jim Continenza added that tariffs on Chinese goods have had no material impact on operations. The warning underscores the 133-year-old firm’s struggle to reinvent itself after a 2012 bankruptcy, as it pivots from film to commercial printing, advanced materials, chemicals and a forthcoming pharmaceutical-ingredients plant.