The six situations in which a bid is invalid as stipulated in the Bidding Law are as follows:

① If a bidding agency violates the provisions of this Law, it divulges information and materials related to the bidding activities that should be kept confidential, or colludes with the tenderee or bidder to harm the national interests, the interests of the public or the legitimate rights and interests of others, the bid will be invalid if it affects the result of winning the bid.

② If the tenderee of a project that must be subject to tender according to law discloses to others the names and quantities of potential bidders who have obtained the tender documents or other information about bidding that may affect fair competition, or discloses the pre-tender estimate, in addition to bearing corresponding legal responsibilities, if it affects the winning result, the bid will be invalid.

③ For a project that must be subject to tender according to law, if the tenderer violates the provisions of this Law and negotiates with the bidder on the bid price, bid plan and other substantive contents, in addition to bearing the corresponding legal responsibilities, if it affects the winning result, the bid will be invalid.

④ if bidders collude with each other or with the tenderee, if the bidders seek to win the bid by bribing the tenderee or members of the bid evaluation committee, the bid will be invalid and they will also bear corresponding legal responsibilities.

⑤ If a bidder bids in the name of others or cheats in other ways to win the bid, the bid will be invalid, and at the same time, it will bear corresponding legal responsibilities.

⑥ If the tenderer determines the winning bidder other than the candidate winning bidders recommended by the bid evaluation committee according to law, if the project subject to tender according to law determines the winning bidder by itself after all bids are rejected by the bid evaluation committee, the winning bid will be invalid, and at the same time, corresponding legal responsibilities will be required.

Conditional bid-winning is invalid and unconditional bid-winning is invalid

As can be seen from the above table, the bid-winning invalidity stipulated in Articles 5, 52 and 55 of the Bidding Law has additional conditions, that is, "if the bid-winning result is affected, the bid-winning is invalid", which is called conditional bid-winning invalidity.

in the process of bidding, three kinds of violations stipulated in Articles 5, 52 and 55 of the Bidding Law do not necessarily lead to the invalidation of the bid. Only when it reaches a certain level, that is, it is enough to affect the result of winning the bid, will the bid be invalid. How to confirm "enough to affect the winning bid"? This should be comprehensively considered from the aspects of the plot of the violation, the degree of influence and the consequences, and finally determine whether the bid is invalid.

However, there are no additional conditions for the bid-winning invalidity stipulated in Articles 53, 54 and 57 of the Bidding Law. As long as one of the listed acts occurs, it will inevitably lead to the legal consequences of the bid-winning, which we call unconditional bid-winning invalidity.

what should I do if the bid is invalid? Article 64 of China's Bidding Law stipulates: "If a project that must be subject to tender according to law violates the provisions of this law and the bid is invalid, the winning bidder shall be re-determined from the remaining bidders according to the bid-winning conditions stipulated in this law or the tender shall be re-conducted according to this law.