Shares of Universal Display Corp. turned around Friday and are now up 12.5%, which would mark the largest single-day percentage gain in a year if the gains hold through the close. Shares were down as much as 3.4% earlier in the day after the company acknowledged a weak market for premium smartphones in its earnings release. However, the company said it expected a rebound later in the year, and analysts were generally optimistic after the numbers came out. The stock is down 42% so far this year, while the S&P 500 has fallen 0.3%.