Buying a new apartment involves several financial and legal formalities. In many cases, people take a loan to buy a house from a bank or non-banking financial company. Two parties are involved in property transactions, namely, the buyer and the seller. However, there are times when a third is included. The third-party becomes a part of the process if you are buying the house with a loan. In most cases, it is a bank. A tripartite agreement is necessary when a buyer applies for a home loan to purchase an under-construction property.