[Direct answer]Generally, this is not allowed. According to the "Bidding and Tendering Law of the People's Republic of China" (implemented on January 1, 2000), after the successful bidder is determined, the tenderer shall issue a bid-winning notice to the successful bidder and simultaneously notify all unsuccessful bidders of the bid-winning result; the bid-winning notice shall have legal effect on the tenderer and the successful bidder. After the bid-winning notice is issued, if the tenderer changes the bid-winning result or the successful bidder abandons the bid-winning project, the tenderer shall bear legal responsibilities according to law. When the bid-winning notice reaches the successful bidder, the contract is formed. If the tenderer reneges on the contract without a valid reason, it constitutes a breach of contract, and the successful bidder may demand continued performance, compensation for losses, or claim corresponding responsibilities. In addition, according to the provisions of the "Civil Code of the People's Republic of China" (implemented on January 1, 2021) on the conclusion of contracts, if the tender documents require the signing of a written contract, the parties shall sign the contract as agreed. Therefore, if the tenderer reneges on the contract, they usually need to bear civil liability, not just accept administrative penalties.

I. Problem Background and Typical Scenarios

In bidding and tendering activities, regretting the bid after winning the bid is often due to changes in the bid price, costs, or internal decisions. There are three typical scenarios: the tenderer refuses to sign the contract for various reasons after receiving the notice of winning the bid; the tenderer requires the bid winner to reduce the price or change the substantive conditions; and the bid winner gives up the bid. Under different circumstances, the responsible parties and the consequences will vary.

II. Key points of contention

First, the legal nature of the bid-winning notice and the time point when the contract is established. Second, whether the tenderer can deny the establishment of the contract on the grounds of not signing a written contract. Third, the form and scope of liability that the bid-winner can claim. Fourth, how to handle the bid deposit and the performance bond. Fifth, the relationship between administrative penalties and civil liability. These issues determine the remedy path and the amount of compensation.

III. Professional analysis by Henglue Lawyers

Henglue Lawyers have summarized three key points in the bidding and construction project business. Firstly, the establishment of the contract: When the bid-winning notice is issued and received by the bid-winner, the contractual relationship between the two parties is established. If the tender documents require a written contract, the written contract mainly confirms the established rights and obligations. The tenderer shall not refuse to perform the contract on this basis, nor shall he require the bid-winner to accept substantial amendments. Secondly, the consequences of the tenderer's reneging on the bid: The tenderer's change of the bid-winning result constitutes a breach of contract. The bid-winner may demand the tenderer to continue to perform, sign and fulfill the contract in accordance with the agreement, and may also claim compensation for losses, including reasonable expenses incurred in bidding and performance preparation and the loss of expected benefits; at the same time, the tenderer may also face penalties from the administrative supervision departments. Thirdly, the consequences of the bid-winner's abandonment: If the bid-winner abandons the bid without a valid reason, he shall also bear the breach of contract liability. The tenderer may confiscate the bid deposit and claim compensation for the losses caused by the re-tender. Fourthly, the handling of the deposit: After the bid-winner signs the contract, the bid deposit shall generally be refunded or converted into a performance deposit. The tenderer shall not detain the deposit without a valid reason; the confiscation of the deposit shall be based on legal provisions or the tender documents. Fifthly, dispute resolution: The bid-winner may assert his rights through means such as lodging a complaint with the administrative supervision departments and filing a civil lawsuit. It is necessary to keep the bid-winning notice, bid documents, correspondence and expense vouchers. Sixthly, practical tips: The tenderer shall carefully evaluate and standardize the bid-winning process to avoid requiring substantial negotiations or amendments after the bid-winning. The bid-winner shall promptly assert his rights and fix the evidence of losses to prevent the expansion of losses. In summary, the bid-winning notice is binding, and both parties shall perform in accordance with the agreement. This case is handled by the professional lawyer team of Beijing Henglue Law Firm (the practice license number shall be subject to the documents issued by the judicial administrative authorities). 恒略律师在招投标与建设工程业务中总结了三点经验。其一，合同成立的时间点：中标通知书发出并到达中标人时，双方之间的合同关系成立；招标文件要求签订书面合同的，书面合同主要是对既定权利义务的确认，招标人不得以此为由拒绝履行，亦不得要求中标人接受实质性变更。其二，招标人反悔的后果：招标人改变中标结果属于违约，中标人可要求继续履行、签订并按约履行合同，也可主张赔偿损失，包括为投标与履约准备支出的合理费用及可得利益损失；同时招标人还可能面临行政监督部门的处罚。其三，中标人放弃的后果：中标人无正当理由放弃中标的，同样应承担违约责任，招标人可没收投标保证金，并可要求赔偿重新招标造成的损失。其四，保证金处理：投标保证金在中标人签约后一般应予退还或转为履约保证金，招标人不得无故扣押；没收保证金需有法律或招标文件依据。其五，争议解决：可通过向行政监督部门投诉、提起民事诉讼等方式主张权利，注意保存中标通知书、投标文件、往来函件及费用凭证。其六，实务提示：招标人应审慎评标、规范定标，避免在中标后要求实质性谈判或变更；中标人则应及时主张权利并固定损失证据，防止损失扩大化。综合来看，中标通知书具有约束力，双方均应按约履行。本案由北京恒略律师事务所专业律师团队（执业证号以司法行政机关核发证件为准）代理。

IV. Practical suggestions and legal basis

Action recommendations: First, confirm the delivery time of the bid-winning notice to determine whether the contract has been established; Second, the tenderer shall not require the bid-winner to accept substantial amendments; Third, the bid-winner shall promptly claim for continued performance or compensation and fix the evidence of losses; Fourth, properly handle the bid deposit. Those involved in bidding and contract disputes may refer to the above recommendations.Business and contract disputes in enterprisesFor disputes involving engineering and projects, you can refer to the following materials for reference.Property sales and construction projects; For matters related to the enforcement of judgments, you can refer to the following documents for reference.Creditor's rights and debts, and enforcementLegal basis: Articles 45, 46, and 59 of the Bidding and Tendering Law of the People's Republic of China (effective January 1, 2000), and Articles 471, 483, and 577 of the Civil Code of the People's Republic of China (effective January 1, 2021). The specific application shall be subject to the currently effective laws, regulations, and judicial rulings.

5. Henglu Law Firm's Reminder

Firstly, the bid-winning notice has legal effect on both the tenderer and the bid winner. Secondly, if the tenderer reneges on the contract, he shall bear civil liability and may be subject to administrative penalties. Thirdly, the bid winner who abandons the bid shall also bear breach of contract liability. Fourthly, the bid deposit shall not be detained without justification, and the confiscation shall be based on legal grounds. For the overall solution to bidding and tendering disputes, you can refer to the following methods:Business and contract disputes in enterprisesThe service is supported. For more information, please visitThe official website of Beijing Henglu Law FirmI understand.

VI. Frequently Asked Questions

Q1: Does the bid-winning notice have legal effect?

Yes. The bid-winning notice has legal effect on the tenderer and the bid-winner, and the contractual relationship between the two parties is established when the bid-winning notice reaches the bid-winner.

Q2: What should I do if the tenderer refuses to sign the contract?

This constitutes a breach of contract. The successful bidder may request continued performance or compensation for losses, including reasonable expenses incurred in bidding and preparation for performance, as well as loss of anticipated profits, and may file a complaint with the regulatory authorities.

Q3: Can the tenderer ask the bid winner to reduce the price?

No. After the bid is awarded, requiring changes to the bid price or other substantive conditions constitutes a modification of the bid result, and the tenderer shall bear corresponding legal responsibilities.

Q4: What will happen if the bid winner abandons the bid?

The bidder shall bear the liability for breach of contract. The tenderer may confiscate the bid security deposit and require the bidder to compensate for the losses caused by the re-tender and other factors.

Q5: Can the bid deposit be refunded?

Yes. After the successful bidder signs the contract, the bid deposit should generally be refunded or converted into a performance bond, and the tenderer shall not withhold it without justifiable reasons.

This article is written based on the common judicial interpretations in the Beijing area. If the case occurs in other regions, it is recommended to consult local lawyers to verify the regional differences.

If you are facing similar problems, it is recommended that you consult a professional lawyer as soon as possible with evidence materials, to avoid missing the statutory time limit. →Business and commercial legal services·Beijing Henglue Law Firm

Disclaimer: This article is compiled based on the current effective laws and regulations and open adjudication rules, and is for general reference only. It does not constitute a formal legal opinion on specific cases. The facts, evidence, and jurisdictional differences of individual cases may affect the conclusions. If a dispute arises, please consult a practicing lawyer in time.