Paid-up capital is the British and Commonwealth term for paid-in capital: the amount of money that shareholders have actually paid to a company in return for the shares it has issued to them. The main entry explains how this capital is recorded in the accounts and what it is made up of.
The two terms are close but not always identical in scope. In United States usage, paid-in capital generally includes both the par value of shares and the premium paid above par. In United Kingdom, Indian and similar company law, paid-up capital often refers only to the nominal value that has been paid, with any premium shown separately in the share premium account. It is distinguished from authorised share capital, the maximum a company may issue, and from issued share capital, which may include shares that are only partly paid, the unpaid balance being callable later.
The figure matters in regulation. Banking, insurance and payment licences commonly set a minimum paid-up capital that must be in place before authorisation, and fully paid ordinary shares are the core of a bank's Common Equity Tier 1 capital. Paid-up capital can be lowered only through a formal capital reduction.