Reuters: Snapchat is struggling to gain traction with advertisers, fuelling investor concern that its $16 billion valuation isn’t justified by a business that hasn’t yet shown it has a steady source of income. Even in a world where upwards of 140 private companies are reckoned to be worth $1 billion or more, Snapchat’s outsized value stands out. Fidelity Investments’ decision to slash the estimated value of its Snapchat stake by 25 percent in the third quarter exacerbated concern about the company’s ability to meet advertisers’ expectations.