The stock market was mixed on Tuesday, with the Dow Jones Industrials flirting with 23,000 on an intraday basis but falling back below that milestone at the close. Generally positive sentiment provided momentum for stocks to climb, but investors still aren't entirely sure whether promised movement on tax reform and healthcare will result in new government policies that will actually bring about desirable results for American businesses. In addition, some stocks suffered from bad news that sent their shares lower. VirnetX Holding (VHC -4.38%), Badger Meter (BMI 16.53%), and MannKind (NASDAQ: MNKD) 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.

VirnetX keeps losing ground

Shares of VirnetX dropped 12%, adding to its losses from Monday following what seemed to be a favorable result in a patent infringement case against Apple (AAPL -0.78%). A Texas federal court entered a final judgment in VirnetX's favor for about $440 million, affirming the value of technology that was used in the iPhone, iPad, and other Apple products. Yet after initially soaring on the news on Monday, shares finished the day lower after Apple said it would appeal. VirnetX seems to be making progress, but litigation is slow, and investors wonder if time isn't working against the small company in its fight against the largest tech company in the world.

Empty courtroom from jury's viewpoint, with room for three judges at front and American flag.

Image source: Getty Images.

Badger sees profits fall

Badger Meter stock dropped 12% in the wake of the company's third-quarter financial report. The maker of flow measurement, control, and communications solutions said that revenue hit a new quarterly record of $100 million, rising 4% from year-ago levels. Yet Badger also reported a 10% drop in earnings per share, and CEO Richard Meeusen cited overall industry softening in holding back the company's growth opportunities. Encouraging news from the oil and gas sector looked like it might soften the blow, but the delay of several major municipal water projects hurt Badger's immediate results. The energy sector is getting more optimistic, but a more favorable view hasn't worked its way into the company's financials just yet.

MannKind gives back some gains

Finally, shares of MannKind declined 12%. The maker of Afrezza inhaled insulin has seen its stock make volatile moves recently, having jumped by more than 250% between mid-September and early October before giving back almost a third of the ground it had picked up since then. MannKind has a lot going for it, but it also is in a somewhat precarious financial situation, with extensive debt that could pose problems in the immediate future. Investors seem less certain about MannKind's prospects today, but if it can refinance its obligations successfully to buy itself some time, the company could end up a big winner if Afrezza takes off.