How do I claim an old mutual fund investment loss from 2011 that I've neglected to claim until now? I have the 1099B for tax year 2011. Is it too late?

I had mutual fund investment loss way back in 2011. At the time I didn't know about claiming losses. 

Now it's tax year 2017. I've obtained 1099B form for 2011 from the brokerage to prove the loss from the sales, now I'm wondering how to claim them.

Is it too late because it's been 6 years?