How should the rise in corporate cash holdings be interpreted?

If we look at non-financial corporations in the largest OECD countries (United States, Canada, United Kingdom, Germany, France, Spain, Italy, Sweden, Japan, Australia), we see a significant rise in their cash holdings since the beginning of the 2000s in all countries except the United States. How should large corporate cash holdings be interpreted? Do they reflect: F ear of a crisis (banking crisis, financial market freeze)? A desire to be able to very rapidly make acquisitions? Simply the existence of profits well in excess of investment opportunities, if they are not used for deleveraging? All three explanations are valid.