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Friday was a quiet end to a tumultuous week on Wall Street, with major market benchmarks giving up much larger gains early in the day to finish with just a modest advance. A combination of strong earnings from the financial sector and reasonably dovish comments on monetary policy from a key Federal Reserve official helped contribute to an overall positive mood, but short-term concerns about various political and economic uncertainties appeared to lead traders to temper their enthusiasm.

Moreover, even though the overall market managed to finish on the high side of unchanged on the day, several stocks were held back by bad news. In particular, Ariad Pharmaceuticals (NASDAQ: ARIA), Infosys (NYSE:INFY), and Natural Health Trends (NASDAQ:NHTC) were among the worst performers on the day.

Ariad gets some unwanted attention

Ariad Pharmaceuticals dropped 15% in the wake of comments on the Twitter feed of former presidential candidate Bernie Sanders, which cited the drugmaker in a negative tweet about the pharmaceutical industry, more generally. The Sanders tweet said that "drug corporations' greed is unbelievable," and then went on to link out to a news article reporting that Ariad had boosted the price of its Iclusig drug for leukemia toward the $200,000 mark for a full year of treatment.

The tweet lacked the "-B" that indicates a direct message from the senator, instead indicating that it came from a staff member. Nevertheless, Ariad investors were spooked by the direct mention of their company, and reacted negatively at the idea that further outrage against pharma and biotech companies could be forthcoming.

Infosys takes another sales outlook hit

Infosys fell 6% after the technology outsourcing and consulting company reported reasonably solid fiscal second-quarter results, but predicted more troubled times ahead. The IT specialist said that revenue rose 8% in the second quarter, with volume and net profit both rising about 4%. However, Infosys reined in its expectations for its top line for the full year, and it now expects year-over-year growth of 8% to 9% in constant currency terms, down from previous double-digit percentage guidance.

Between contract cancellations that are arguably connected to the Brexit decision, and currency volatility, Infosys could continue to have trouble predicting its near-term results unless things start to settle down.

Natural Health Trends warns of an unhealthy quarter

Finally, Natural Health Trends plunged 16%. The company warned that its third-quarter results would be weaker than investors had expected, with the marketer of personal care, wellness, and other products estimating that sales dropped 12% from year-ago levels.

Natural Health Trends cited security measures in advance of the G20 Summit in China that it said kept its members from conducting business activity in the area, and the Chinese currency's decline in value compared to the Hong Kong dollar also had negative pricing implications for customers. Natural Health Trends will announce final results the week after next, but investors didn't wait for confirmation before sending the share price markedly lower.

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