1. Regardless of whether it is a contract or a contract, stamp duty must be paid. This is determined by the nature of stamp duty;

2. The stamp duty on construction projects is three ten thousandths of the contract amount, and there is no time limit, as long as the stamp tax is paid before the tax audit.

For example:

Company A and Company B form a consortium to undertake a construction project, and sign a construction contract worth 500,000 yuan with owner C. The contract states that A is responsible for the construction project. The construction cost is 200,000, and B is responsible for the construction project cost of 300,000. How much stamp duty do companies A, B, and C each pay?

A and B, as overall undertaking parties, appear in the same contract as the client. A and B as a whole calculate and pay tax based on the contract amount of 500,000 yuan. The sharing between A and B can be based on the cost sharing amount in the contract or other supplementary agreements. Company C calculates and pays stamp tax based on the contract amount of 500,000 yuan.