Businesses require finance for starting up, day-to-day operations, and unexpected expenses. Sources of finance can be internal, like retained profits or asset sales, or external through loans, shares, or debentures. Short term finance is needed for under a year and can come from overdrafts, trade credit, or loans. Medium term finance for 1-5 years includes leasing and hire purchase. Long term external finance over 5 years includes shares, debentures, and long term bank loans. The appropriate source of finance depends on the amount needed and the length of time for which it is required.