银行投标保函，又称投标担保，是指由银行（担保人）应投标人（申请人）的请求，向招标人（受益人）开立的，保证投标人在投标有效期内遵守招标文件规定，不撤回投标文件，并在中标后按规定签订合同并提交履约担保的书面保证承诺。若投标人在投标有效期内撤回投标文件，或中标后拒绝签订合同或提交履约担保，银行将按保函约定向招标人支付一定金额的赔偿金，最高不超过保函金额。
A bid bond, also known as a tender guarantee, is a written guarantee commitment issued by a bank (guarantor) at the request of a bidder (applicant) to a tenderee (beneficiary), ensuring that the bidder will abide by the provisions of the tender documents during the bid validity period, will not withdraw the bidding documents, and will sign the contract and submit a performance bond as required after winning the bid. If the bidder withdraws the bidding documents during the bid validity period or refuses to sign the contract or submit a performance bond after winning the bid, the bank will pay a certain amount of compensation to the tenderee according to the bond agreement, which shall not exceed the bond amount.
投标保函的设立主要是为了维护招标投标活动的正常秩序，保护招标人的合法权益。具体而言，投标保函具有以下作用:
The establishment of a bid bond is mainly to maintain the normal order of bidding and tendering activities and protect the legitimate rights and interests of tenderees. Specifically, bid bonds have the following functions:
1. 保证投标的严肃性: 投标保函的存在可以约束投标人的行为，防止投标人随意撤回投标文件或中标后不履行义务，从而保证招标过程的严肃性和公正性。
1. Ensuring the seriousness of bidding: The existence of a bid bond can restrain the behavior of bidders and prevent them from arbitrarily withdrawing bidding documents or failing to fulfill their obligations after winning the bid, thus ensuring the seriousness and fairness of the bidding process.
2. 保护招标人的利益: 如果投标人在违反投标承诺的情况下，招标人可以通过投标保函获得一定的经济补偿，以弥补因投标人违约而造成的损失。
2. Protecting the interests of tenderees: If the bidder violates the bidding commitment, the tenderee can obtain certain financial compensation through the bid bond to compensate for the losses caused by the bidder's breach of contract.
3. 提高招标效率: 投标保函的存在可以提高招标人的信心，吸引更多有实力的投标人参与投标，从而提高招标的效率和质量。
3. Improving bidding efficiency: The existence of a bid bond can enhance the confidence of tenderees, attract more capable bidders to participate in the bidding, and thus improve the efficiency and quality of bidding.
根据开立方式的不同，银行投标保函主要分为以下几种类型:
According to different issuance methods, bank bid bonds are mainly divided into the following types:
1. 独立保函: 独立保函是指银行仅凭保函条款的约定承担独立的付款责任，而不受基础合同的影响。即使基础合同无效，银行也需要按照保函的约定进行赔付。
1. Independent Guarantee: An independent guarantee refers to a guarantee in which the bank assumes an independent payment obligation only based on the agreement of the guarantee clauses, without being affected by the underlying contract. Even if the underlying contract is invalid, the bank still needs to make compensation according to the agreement of the guarantee.
2. 见索即付保函: 见索即付保函是指受益人只要提出索赔，并提交符合保函要求的文件，银行就必须无条件地、立即支付赔款的保函。
2. On-demand Guarantee: An on-demand guarantee refers to a guarantee that the bank must unconditionally and immediately pay compensation as long as the beneficiary makes a claim and submits documents that meet the requirements of the guarantee.
3. 有条件保函: 有条件保函是指银行只有在受益人提交了符合保函要求的文件，并证明申请人确实违反了合同约定时，才会履行付款责任的保函。
3. Conditional Guarantee: A conditional guarantee refers to a guarantee in which the bank will only fulfill its payment obligation when the beneficiary submits documents that meet the requirements of the guarantee and proves that the applicant has indeed violated the contract agreement.
企业申请银行投标保函的一般流程如下:
The general process for enterprises to apply for bank bid bonds is as follows:
1. 咨询申请: 投标人向银行咨询投标保函业务，并提交相关资料，如营业执照、企业简介、招标文件等。
1. Consultation and Application: The bidder consults the bank on bid bond business and submits relevant materials, such as business license, company profile, tender documents, etc.
2. 银行审核: 银行对投标人的资质、信用状况、财务状况等进行审核，评估其风险程度。
2. Bank Review: The bank reviews the bidder's qualifications, credit status, financial status, etc., and assesses its risk level.
3. 缴纳保证金或提供反担保: 银行根据审核结果，要求投标人缴纳一定比例的保证金，或提供其他形式的反担保，如房产抵押、第三方担保等。
3. Paying Margin or Providing Counter-guarantee: According to the review results, the bank requires the bidder to pay a certain percentage of margin or provide other forms of counter-guarantee, such as real estate mortgage, third-party guarantee, etc.
4. 签署协议: 银行与投标人签署投标保函协议，明确双方的权利义务及违约责任。
4. Signing Agreement: The bank signs a bid bond agreement with the bidder to define the rights and obligations of both parties and the liability for breach of contract.
5. 开立保函: 银行在收到投标人缴纳的保证金或反担保后，正式开立投标保函，并将正本传递给招标人。
5. Issuing Guarantee: After receiving the margin or counter-guarantee paid by the bidder, the bank officially issues the bid bond and delivers the original to the tenderee.
企业在办理投标保函业务时，需要注意以下事项:
Enterprises should pay attention to the following matters when handling bid bond business:
1. 选择信誉良好的银行: 银行的信誉和实力直接关系到保函的效力和执行力，建议选择规模较大、信誉良好的银行办理业务。
1. Choosing Reputable Banks: The reputation and strength of a bank directly affect the validity and enforceability of a guarantee. It is advisable to choose a large-scale and reputable bank to handle the business.
2. 仔细阅读保函条款: 在签署保函协议前，应仔细阅读保函条款，特别是关于保证责任、免责条款、索赔程序等内容，避免因理解偏差而产生纠纷。
2. Carefully Reading the Guarantee Clauses: Before signing the guarantee agreement, carefully read the guarantee clauses, especially the contents about guarantee liability, disclaimer clauses, claim procedures, etc., to avoid disputes due to deviations in understanding.
3. 合理安排保证金
