A pair of exchange-traded products that offer leveraged exposure to a group of popular large-capitalization internet and technology companies saw heavy trading and sharp moves on Monday, as Facebook's stock suffered one of its worst days in years. The BMO REX MicroSectors FANG+ Index 3X Leveraged ETN FNGU, -8.88% sank 11% and traded on heavier-than-average volume. The exchange-traded note offers triple-leveraged exposure to an index of 10 stocks, returning 300% of that index's daily move. The index is geared toward the so-called 'FAANG' group of stocks, which refers to Facebook FB, -6.77% Amazon AMZN, -1.70% Apple AAPL, -1.53% Netflix NFLX, -1.56% and Google-parent Alphabet GOOGL, -3.03% All those stocks were lower on Monday, dropping at least 2%, with Alphabet down 3.7%. The biggest losses were in Facebook, however; the social-media giant sank 6.5% as it came under heavy criticism for how it has managed user data. The BMO REX MicroSectors FANG+ Index -3X Inverse Leveraged ETN FNGD, +8.58% rallied 10% on Monday; the note is designed to rise when the underlying components fall. The Dow Jones Industrial Average DJIA, -1.35% fell 1.7% while the S&P 500 SPX, -1.42% lost 1.8% and the Nasdaq Composite Index COMP, -1.84% was down 2.3%.