Here are the biggest calls on Wall Street on Wednesday: Baird initiates Abbott Labs as outperform Baird says the company has a robust portfolio. "Despite near-term pressures, we see ABT's portfolio delivering steady 6-8%/LDD top-line/earnings growth over the next several years, leveraging a portfolio of (a) MedDevices, with exposure (and leading positions) in the largest, fastest-growth end-markets, supporting an above peer ~8-10% MedDevice growth trajectory and (b) Diagnostics/Nutrition/Established." Jefferies upgrades Murphy USA to buy from hold Jefferies says it sees fuel margins improving. "We are upgrading MUSA to Buy as improving fuel margins and stronger execution drive a materially higher…