My latest stories on exchange-traded funds are both about the competition brewing among ETF firms to gather assets.

The first highlights strategy-based or factor ETFs being launched by several firms to mimic stock-picking methodologies. Many of these are new and untested. The second recaps a recent fee tussle between StateStreet and PowerShares over a collection of financial indexes.

The current phase of ETFs - dubbed 3rd gen by some - may also lead to significant consolidation as many funds and fund companies have been on the market long enough to know if their approach is working.