Even after smaller stocks soundly beat the market the last 12 months, Chuck Royce believes the asset class will continue to rise for several more years.
The Russell 2000 index is up 23 percent in the past year through Monday versus the S&P 500's 15 percent return through Monday.
CNBC's Mike Santoli spoke with Royce in an exclusive interview for CNBC PRO. Santoli asked the investor about his outlook for small-caps, which experienced a decline of more than 25 percent from mid-2015 to early 2016.
"When small caps have declined more than 15 percent you tend to get pretty dramatic runs over a period of time. Maybe as much as 100 percent on average, so we really are nowhere near that level," Royce said.
Small-cap "value tends to have a pretty long run. Certainly, the last long run was right after the internet boom. So after the internet boom you really had almost seven years, value did superbly. I'm not sure it will be seven years, but I certainly think it's much more likely 3, 4, 5 years. So we're about a year and change into it. So I'm very comfortable saying this has a long way to go," he added.
Royce is chairman of Royce & Associates, a small-cap specialist investment management firm with nearly $18 billion in assets which he founded in 1972.
The small-cap portfolio manager also revealed why the rise of ETFs is creating opportunities for fundamental stock pickers:
"ETFs have setup highly correlated behaviors in certain stocks if it's part of an index. The Russell  has become a very popular ETF, billions of dollars [are] in the Russell. That has in a sense left out a range of stocks that are … not in the Russell that might become more interesting because a relative prices advantage is being setup. So it's creating, I think in the long run, actually opportunity for an active investor."