What is the difference between a Stock sale or an asset sale?

In a stock sale, the buyer purchases all or a portion of the stock (or membership interest in the case of an LLC) of a business entity. In most cases, the purchase would be at least for a controlling (majority) interest. The business entity itself continues to exist as before, there is simply a change of ownership. Notably, if the business entity owed people money before the stock sale, it will continue to owe that money after the stock sale, so the new owner effectively assumes all of the obligations of the business.

In an asset sale, the buyer only purchases assets from the business. Unless the buyer agrees to assume specific liabilities (or, in some instances, if there are specific liabilities that follow the assets, by law), the buyer is not responsible for paying the debts of the selling company. After the sale of the assets, the old company continues to have the responsibility to pay its creditors.