Big business people are big due to their investment and they have no saving but they have creative mind and they used that mind to take debt for the business and now they are paying zero tax legally.
Businesses, big and small do have savings. Big corporations are majorly big cause they've got investments all over that bring in profits. Doesn't mean there isn't any savings. You can literally have both savings and investments. These large corporations definitely have money saved and reserved to guard against unforeseen events that could be detrimental and may hinder the profits from rolling in.
Also, new and hot projects that were not planned for are invested in using money that is saved up.
Having savings is like having a safety net on a construction site. It helps guard against unforseen circumstances. What business wouldn't have some savings?