Thursday was a down day on Wall Street, with major benchmarks falling significantly from recent highs. The Dow Jones Industrials were down by triple digits for much of the session as investors responded to the ongoing wrangling on Capitol Hill over tax reform. With the House plan already having been released, initial reports about the Senate's impending proposal suggest that it takes a very different approach, with considerable chances of less-aggressive changes. Delays in corporate tax cuts and the removal of bracket-simplifying provisions were disappointing to some advocates of reform, and the resulting uncertainty could make it hard for lawmakers to get a plan done by the end of the year. In addition, some stocks had company-specific bad news that hurt their shares. Canadian Solar (NASDAQ:CSIQ), Ambac Financial (NASDAQ:AMBC), and Maiden Holdings (NASDAQ:MHLD) were among the worst performers on the day. Below, we'll look more closely at these stocks to tell you why they did so poorly.

Canadian Solar gets stuck in the shade

Shares of Canadian Solar dropped 11% after the solar manufacturing specialist reported its third-quarter financial results. The company said that revenue jumped by more than 30% from what it brought in three months ago, with solar module shipments of 1,870 megawatts dramatically outperforming past guidance for between 1,650 and 1,700 megawatts. Earnings were disappointing compared to what those following the stock had expected to see, however, and some investors seemed unsatisfied with efforts to keep raw materials costs down and monetize its operating solar power plants. With the rest of the industry seeing good conditions, Canadian Solar will need to play catch-up quickly in order to bounce back from its sluggish performance.

Solar panels on a barn building rooftop on a large farm, on a sunny day with yellow fields surrounding the buildings.

Image source: Canadian Solar.

Ambac deals with Maria's aftermath

Ambac Financial stock plunged over 16.5% in the wake of the company's third-quarter financial report. The bond insurance company has considerable exposure to bonds issued by the U.S. territory of Puerto Rico, and even before the quarter began, concerns about Puerto Rico's ability to repay its massive debt had caused Ambac considerable trouble. After Hurricane Maria slammed into the territory and caused widespread catastrophic damage across the island, Ambac faced an even bigger challenge, and massive losses related to the disaster caused the insurer's book value to plunge more than 13%. With no solution to Puerto Rico's problems in sight, investors have to hope that Ambac can keep repositioning itself to diversify its risk profile and somehow work its way through its exposure to the island territory.

Maiden takes some hurricane hits

Finally, shares of Maiden Holdings plummeted 22%. The insurance company suffered dramatic losses during the third quarter of 2017, reversing a year-earlier profit. The company said that net negative impact from catastrophic events during the period amounted to $20 million, which was about a third of the money that Maiden lost for the quarter. Yet fundamental weakness also played a role in Maiden's tough quarter, including premium-writing activity that was down more than 10%. CEO Art Raschbaum pointed to some positive aspects of the quarter, including better investment earnings and strong premium growth in the diversified reinsurance segment. Often, high-loss events are long-term positives for insurance and reinsurance companies, but investors in Maiden Holdings couldn't get past the short term in their assessment of the insurer's performance.

Dan Caplinger has no position in any of the stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. The Motley Fool has a disclosure policy.