Copied from Tax Pro Today:
Expired tax breaks
Approximately 30 tax breaks that had been given short-term extensions over a number of years expired at the end of 2017. There had been some debate as to whether those tax breaks would continue after the Tax Cuts and Jobs Act, but Congress extended them through 2017 in early 2018, resulting in some need to revise software systems and tax forms for the 2017 tax return filing season. Congress is again considering what to do with those expired provisions well after their expiration. The initial proposal had been to extend them retroactively for 2018 and preserve them for 2019. As time passes without enactment, however, the chances increase that many of those expired provisions will not be extended. Another issue that may push some of the tax breaks to the sidelines is that Democrats would prefer that any extension be paid for, but offsetting revenue-raisers appear to be in short supply. Besides a few individual tax breaks, most of the expired provisions relate to energy or to specific industries. Democrats have been working on a more simplified structure for energy tax breaks, focused on renewable energy, and that initiative might replace many of the energy-related expired tax breaks.
Lobbying activity continues in an effort to restore a number of these tax breaks, including credits for biodiesel and railroad track maintenance, but, as time passes without action, the number of expired provisions likely to receive retroactive extension, or any extension at all, continues to diminish.