No share capital is the capital that the owners of the business have contributed. Its not a liability, its just the capital invested. The company does not have a liability for this capital contribution to the shareholders. They have the right to sell their shares to third parties but the company does not have an obligation to re-buy the shares and hence no liability arises.
The share capital is part of the equity section on the balance (or the statement of financial position as it’s called). Remember that the accounting equity is :
Assets= Liabilities + Equity.
The equity included the share capital that the company has issued plus the reserves (share premium, profit and loss, revaluation reserves etc.).