1. The difference between the construction unit and Party A is as follows:

(1) The construction unit refers to the investor of the construction project and owns the property rights of the project;

(2) Party A generally refers to the developers in the real estate industry;

(3) When Party A is a real estate agent, both the construction unit and Party A are real estate agents.

2. Legal basis: Article 46 of the Measures for the Administration of Bidding for Building Construction and Municipal Infrastructure Construction.

The tenderer and the winning bidder shall, within 30 days from the date of issuance of the bid-winning notice, conclude a written contract according to the tender documents and the bid documents of the winning bidder; The tenderer and the winning bidder shall not conclude other agreements that deviate from the substantive contents of the contract.

If the winning bidder does not sign a contract with the tenderer, his bid bond will not be refunded and his bid winning qualification will be cancelled. If the losses caused to the tenderer exceed the amount of bid bond, compensation shall be made for the excess; If the bid bond is not submitted, it shall be liable for the losses of the tenderer.

If the tenderer fails to sign a contract with the winning bidder without justifiable reasons, thus causing losses to the winning bidder, the tenderer shall make compensation.

Article 47

If the tender documents require the winning bidder to submit the performance guarantee, the winning bidder shall submit it. The tenderer shall also provide the bid winner with a guarantee for payment of the project funds.

Second, what are the scope of invalid bidding documents?

Invalid bidding documents are as follows:

1, the bid documents are not sealed as required by the tender documents;

2. The tender letter in the tender documents is not stamped with the seal of the bidder's enterprise and the legal representative of the enterprise, or the legal representative of the enterprise does not have the legal and effective original power of attorney and the seal of the entrusted agent when entrusting the agent;

3. The key contents of the bid documents are illegible and illegible;

4. The bidder fails to provide bid security or bid bond in accordance with the requirements of the tender documents;

5. If the consortium bids, the bidding documents are not attached with the bidding agreement of the parties to the consortium.