Summer is on the way, so isn’t it time to do some work on your core…core exchange traded funds (ETFs) within your portfolio, that is.

The underlying indexes within these ETFs are blended with United States, developed foreign and emerging foreign markets, explains Roger Nusbaum for Seeking Alpha.

Examples of core ETFs include Vanguard All-World ETF (VEU) and iShares All-World (ACWI). Northern Trust (NTRS) has one on the way. These ETFs have the purest exposure because of the blend of attributes and components. They’re interesting products, and it will be fun to see how they perform

These funds have him wondering just how lazy a portfolio can be while still adding value. In addition to buying the world, he would add an absolute return fund to smooth out the bear markets. An investor could do okay averaging 8% from the all-world fund and 5% from the absolute (provided you’re saving, too).

The opinions and forecasts expressed herein are solely those of Tom Lydon, and may not actually come to pass. Information on this site should not be used or construed as an offer to sell, a solicitation of an offer to buy, or a recommendation for any product.