Airbnb is on track to be profitable for the second straight year, as measured by earnings before interest, taxes, depreciation and amortization. In 2017, the company posted $100 million in profit on $2.6 billion in revenue, said the source. CEO Brian Chesky said the company would be ready to go public by mid-2019, but the company hasn't decided when. Airbnb is one of the most valuable start-ups in the US at $31 billion. Get the full story at CNBC