For the ETF industry, 2014 went out with a bang. On Dec. 22, total assets in roughly 1,600 U.S. exchange traded funds reportedly topped $2 trillion. That milestone confirmed a stock market rally that saw SPDR S&P 500 (ARCA:SPY) rise 13.5% last year. But out with the old and in with the new. We asked investment pros to provide their outlook for 2015 and top picks for ETF investing. J.J. Schenkelberg, senior portfolio manager with CLS Investments in Omaha, Neb.; assets under management: $6.6 billion: We are cautiously optimistic regarding stock performance in 2015. While the U.S. economy continues to move forward, valuations are stretched. Relative price opportunities are more attractive internationally; however, we need to see a turnaround in economic growth. Increased volatility is likely. Read More At Investor’s Business Daily: http://news.investors.com/investing-etfs/010515-733221-positive-views-reign-on-stock-market-outlook.htm#ixzz3O5PnYfjS Follow us: @IBDinvestors on Twitter | InvestorsBusinessDaily on Facebook