Airbnb posted its second straight year of profitability on an adjusted basis as it heads toward a possible IPO, the start-up announced Tuesday.

Airbnb is one of several giant private tech companies gearing up for a public debut this year, alongside Uber, Lyft and WeWork. But Airbnb is eyeing the offering with two years of EBITDA profits, according to a company memo seen by CNBC. EBITDA is a measure of operating profits before financing-related expenses like interest, taxes, depreciation and amortization.

The company expects to hit 500 million guest arrivals by the end of the first quarter this year — that's the number of completed bookings since the company's founding in 2008. That would be 100 million new guest arrivals since its last stated total in September 2018.

Airbnb isn't breaking out any other numbers, like annual revenue, but the increase in guest arrivals signals rapidly accelerating growth and a promising outcome of an eventual public debut. In the third quarter of 2018, the company told CNBC that it had passed $1 billion in quarterly revenue. The company was valued at over $30 billion in financing rounds in 2016 and 2017.

Airbnb CEO Brian Chesky told Recode last May the company will be "ready to IPO next year, but I don't know if we will." The company hired a chief financial officer in November, filling a long-vacant seat and hinting that it was shoring up its finances.

WATCH: Airbnb hires new CFO from Amazon