AppNexus just became a billion-dollar entity. The company, based in New York, specializes, focuses on real time online advertising. It has nearly doubled its company's value after announcing that it has acquired additional funds from new sources. Now valued at $1.2 billion, AppNexus is notably the most remarkable tech start-up in New York, overtaking Tumblr, which was acquired by Yahoo last year for a whopping $1.1 billion.

According Yahoo, around $60 million dollars is said to have come from a large unnamed equity and management firm based in Boston. Another $40 million is expected to come from various investors after it gains some attention from Wall Street.

Investors are quite confident about putting money in AppNexus now especially after the company declared a profit in the first quarter of 2014. The reach of AppNexus is vast. It only comes in second to Google. AppNexus is basically a tech company that provides advertisers and publishers the platform to trade ads. Simply put, digital ads are bought and sold in real time through the web.

Brian O'Kelley shares his views on the valutation of the company and its investors: "We needed to be able to go to companies and say, we are as good as a public equity. We can't disclose our investor, but these guys don't play games."

"It's a clean, real valuation we can take to the bank and use to acquire companies and show employees the incredible value of our stock." O'Kelley adds according to Forbes.

Venture capitalists have pumped blood into the veins of AppNexus. Currently, over $200 million in funds have been generated through the likes of SV Angel, First Round, Andreessen Horowitz, Khosla Ventures and Venrock. To ensure liquidity, AppNexus has also taken the initiative to acquire a $75 million credit facility with Silicon Valley Bank. Most of the newly acquired lines will be used to fund new acquisitions.

CEO Brian O'Kelly, the self-proclaimed inventor of real time ad exchange or trade, has been very strategic. Getting the valuation of AppNexus to $1.2 billion certainly makes it harder for others to get a piece of it. In the meantime, it will continue its efforts to strengthen its value by performing well. The company's profitability is expected to improve this 2014. If the growth and momentum is sustained, the next step is to go public: the IPO route.