Catch up on today's top five analyst initiations with this list compiled by The Fly: 1. Ultragenyx (RARE) assumed with an Overweight at Piper Jaffray. 2. Trivago (TRVG) was initiated with a Buy at Mizuho while TripAdvisor (TRIP) and Expedia (EXPE) were initiated with a Neutral. 3. Miragen Therapeutics (MGEN) initiated with a Buy at Deutsche Bank. 4. Arris (ARRS) assumed with an Equal Weight at Barclays. 5. Sientra (SIEN) initiated with a Buy at Maxim. This list is just a portion of The Fly's analyst coverage. To see The Fly's full Street Research coverage, click here.