Giving Pledge Adds Ultra-Rich Members to Donate Their Wealth

The Giving Pledge has brought on 11 new signatories in its latest effort to spur philanthropy of the ultra-wealthy.

Billionaire Dropbox Inc. co-founder Drew Houston and Invisibly founder Jim McKelvey, along with their spouses, are among the group that has penned letters promising to give away the majority of their wealth in their lifetime or their will.