The risk of commodity trading activities in a market economy is the uncertainty of future losses or gains, or the difference between the expected possible results under certain circumstances. Risk has the basic characteristics of futurity, uncertainty, loss, specific root cause, universality, loss can be measured by probability, transferability and so on. According to availability, risks can be divided into two categories: pure risks and speculative risks. Pure risk will only cause loss or no loss, but can not provide profit opportunities; However, speculative risk may not only cause losses, but also provide profit opportunities. These characteristics determine the risk prevention, and the risk loss can be controlled. However, the construction project transaction is different from the commodity transaction in general economic activities, which has the basic characteristics of the unity of product transaction and factor transaction, the owners and contractors are trading under incomplete information, multi-stage transaction, complex terms of the transaction contract and so on.

Due to these transaction characteristics of construction engineering, construction engineering is a high-risk industry. There are many reasons for the high risk of construction industry, mainly determined by the inherent characteristics of construction products: (1) The construction period is long. General projects last for several months, and larger projects last for more than one year. A world-famous mega-project like the Three Gorges Project has a construction period of several generations. (2) Open-air operation is greatly influenced by natural uncertainties. The whole process of engineering construction is actually a game between man and nature. The contractor has to face severe climatic conditions such as severe cold, intense heat, typhoon and flood, and deal with complex and changeable geological conditions, such as landslides, subsidence, underground undercurrents and differences in geological conditions. (3) It is greatly influenced by the changing factors of policy environment and market environment. Due to the long construction period, these external factors, especially the market economy factors, often change frequently during the construction period, and the most typical and common encounter is the risk brought by the rising price of building materials caused by inflation. (4) It is greatly influenced by human factors. The transaction of construction projects is accompanied by the transaction of labor factors. Assuming that one side of the transaction is an opportunist, or even a person who doesn't speak credit, it is easy to cause risks to the other side.

Engineering construction risks can be divided into two types: man-made risks and natural risks. Man-made risk refers to the risk that the economic loss of a construction project is directly caused by human factors, or indirectly caused by other factors related to human activities such as economic factors, political factors and social factors. Natural risks refer to the losses caused by harsh natural conditions and accidents, including the risks of economic losses caused by climate, surrounding environment and site conditions. These two risks can occur independently, and sometimes they can affect each other. If people's construction activities can cause natural disasters, such as developing mountains, it is easy to cause landslides, causing casualties and major economic losses; On the other hand, natural disasters will aggravate man-made risks. After the catastrophic flood, the soaring price of building materials caused the project budget to get out of control. Sometimes people's construction activities can also control natural disasters, such as flood control by water conservancy projects; Good natural conditions can also reduce man-made risks. Winter in Shenzhen is the golden season for construction, which can save a lot of construction costs compared with rainy season.

2. Risk categories of sealed bidding for construction projects

The effective selection of construction project suppliers is determined by the owner's public bidding, and the winning bid method (also known as sealed bidding without base price) is the basic bidding method adopted by developed market economy countries or regions. Generally speaking, there are two kinds of risks in its bidding: one is the transcendental risk that the bidder can preliminarily estimate or predict according to the previous experience of engineering construction or commodity production, as shown in Rothkopf, Wilson, Milgrom &; Robert, Maskin & Riley and Offerman &; Gerry and other scholars have done a lot of research on the theory of bidding and auction; The other is the post-event risk involved in the process of the bidder's performance of the corresponding contract after winning the bid. For example, when bidding, the cost or price of a project or item is underestimated or even too low, and it is found that the cost of the project or item exceeds its own bidding price during the performance of the contract, and it faces losses, which is the case with McAfee &; Macmillan and ESO&; It is involved in the literature of scholars such as White.

The risk of sealed bidding for construction projects is caused by the defects in the market structure or conditions of construction projects, changes in human factors, economic factors, political factors and social factors. Risks related to this bidding method mainly include the following aspects:

The first is the speculative risk of bidders. Bidders take advantage of the imperfection of the legal system and the loopholes in the bidding documents or construction contract documents to adopt the bidding strategy of winning the bid below the cost price, and then claim for compensation at a high price during the construction process, causing losses to the tenderee. If the claim fails, the contractor may be unable to perform the project according to the contract due to losses, which will also cause losses to the tenderer. In addition to legal and contractual reasons, this situation is related to the imperfection of social credit and personal credit system, and there is not much difference between talking about credit and not talking about it. After this project is broken, other projects will continue to be fired. Because the bid of sealed bidding is produced by fierce price competition, even if the bid is higher than the actual cost, its profit is very thin, and the contractor's ability to resist risks is weak, which is exactly where people doubt this bidding method. At present, China's construction laws and regulations are not perfect, and people's traditional consciousness has not changed, that is, they are completely unaware that construction is a high-risk industry, and the construction engineering trading market is full of speculation. Because our country punishes the illegal acts in the process of bidding and the breach of contract in the process of contract performance lightly, it objectively encourages speculation in the construction of trading market. Individual or subcontracting behavior in the construction market also increases the occurrence of speculation, because if the money is personal after winning the bid, the loss can be pushed to the unit or others. In the incompletely standardized construction project trading market, there are three bidders with different risk preferences: risk-seeking, risk-neutral and risk-avoiding. Not only has it been shown in theory that the quotation of risk-seeking bidders is relatively lower than that of risk-neutral and risk-averse bidders, and it is easy to win the bid, but also the results of our social practice questionnaire survey show that winning the bid by risk-seeking bidders is risky for the owners.

The second is the collusion risk of bidders. There are two kinds of collusion risk, one is the collusion risk between bidders. The characteristic of the construction project trading market is that the effectiveness of the effective monopoly of the tenderee (buyer) lies in that multiple bidders (sellers) provide "construction products", and the bidder with price advantage wins the competition. Then, this validity may be invalid because of the collusion of bidders. If * * * can be reached between bidders before bidding and the high quotation strategy can be formulated uniformly, so as to win the bid in turn or conduct secondary bidding within its scope, the project will be awarded to the bidder who can benefit other bidders who participate in bidding, or allocated by the winning bidder, and several bidders will jointly complete the bidding project. When this phenomenon occurs, it is usually called "bidding" and "collusion". When collusive bidding occurs, it will break the complete free competition in the construction project trading market and form oligopoly collusion in the construction project market. When one or several bidders monopolize the project by colluding in bidding or colluding in bidding, they will definitely raise their quotations from their own interests and make the tenderee suffer. George stigler (1964) pointed out that the best way to embody the principles of fairness, justice and openness in government procurement should be sealed bidding (auction), but collusion prevented bidders from making fair and reasonable quotations.

Larry Yuspeh (1976) confirmed that Carter (in the form of collusion among bidders) will significantly reduce the degree of competition brought about by the increase in the number of competitors and significantly increase the bid price. The other is the collusion risk between insiders and outsiders. Refers to the collusion between the internal personnel of the tenderer and the internal and external personnel of the bidder to help a specific bidder win the bid. This situation is easy to happen when the tender conditions are completely determined by the tenderer himself, the sealed pre-tender price is compiled, bidders are invited and the bid evaluation target is organized. In that case, you can only win the bid if you know the sealed reserve price, which often becomes the key point of internal and external collusion. At present, all engineering projects have entered the construction project trading market for bidding activities, and public pre-tender bids have been implemented. At the same time, this kind of internal and external collusion is difficult to happen when bidding by sealed bidding. Because any bidder can win the bid with the lowest price, even if he doesn't know the tenderer at all, it has no influence on the project subject to tender without knowing it in advance. This can also be considered as a major advantage of the sealed bidding method.

The third is the adverse selection and moral hazard of bidders. The so-called adverse selection here means that in the bidding process, due to information asymmetry, bidders will hide information that is not conducive to them in order to win the bid, and at the same time, because the tenderer is not easy to obtain this information, or the acquisition cost is too high, it is impossible to understand this information that has an impact on the quality or cost of the project. Due to information distortion, the adverse selection of bidders will lead to the risk of the original effective monopoly of the construction project trading market structure. The problem is that the construction project trading market is mixed, which makes it possible for the tenderer to obtain a beautiful but invalid tender and choose an unsuitable contractor, thus bringing potential risks in construction. The construction project trading market needs a mechanism to reveal the true information of bidders. Moral hazard afterwards. Because a remarkable feature of project bidding is to "place an order" first and then "produce". In other words, first determine who to buy, and then let who complete the construction project according to the requirements agreed in advance. Due to the incompleteness of the contract, the future and uncertainty of the risk, and the imperfection of relevant laws and regulations, the bidder has moral hazard. In the bidding process, in order to win the bid, the bidder will try to lower the bid price, or even quote at a price lower than the cost, as the beginning of the negotiation, and then change the scheme and standard in the subsequent substantive technical negotiation to achieve the purpose of re-quoting and raising the bid price, or increase the cost by increasing the on-site visa during the construction process, so that the final contract price or final settlement price is higher than the original bid-winning price. Another post-event risk is caused by the long construction period, which is one of the characteristics of construction projects. Once the bidding process is over, the contractor is determined, which is actually the end of the tenderee's effective monopoly of the construction project market competition. In order to get more profits, or because the original contract price is very close to the cost price, in order to make up for the losses, the contractor may cut corners in the construction and reduce the quality of the project to reduce the cost.

The fourth is the risk of bidding failure. Refers to the deficiency of the bidding method itself in structural design or operation process design; Or the lack or change of external conditions in the bidding market leads to the inadaptability of market conditions to the bidding method, which leads to the inefficiency or failure of the bidding method, fails to play its due role in reducing the project cost, and increases the investment risk of the tenderer in disguise; Or because an unsuitable bidder is selected to win the bid, the unsuitable bidder cannot perform the contract and provide the owner with construction products with good quality and quantity on time, thus causing losses to the tenderer. If there are shortcomings in the structural design and operation flow design of the bidding method, it will definitely affect the bidding result and fail to achieve the purpose of selecting the best and reducing the cost. In addition, because each bidding method can only be applied to certain external market conditions and technical management requirements, even if the bidding method itself is feasible in theory, if there is no matching external market conditions and technical management requirements, it will also affect the effectiveness of the bidding method and may lead to bidding failure.

The fifth is the risk of engineering uncertainty. Engineering construction itself is a high-risk industry, and there are many reasons for the formation of high risks, and the uncertainty in engineering is the main reason. It can be divided into two kinds: artificial uncertain factors and natural uncertain factors. An inherent feature of building engineering products is the long construction period, during which the cost of production factors of building engineering is easy to change, thus causing losses to the project. The uncertain factors of production factors in the construction trading market belong to man-made uncertain factors; The second feature is that construction projects are greatly influenced by natural uncertainties and difficult to predict. During and after the project construction, they are often attacked by natural disasters and emergencies, causing huge economic losses. Objectively speaking, the risk of engineering uncertainty exists in any bidding method and is not unique to the sealed bidding method. It is only because the mechanism design of sealed bidding method forces bidders to win the bid with the lowest quotation. Compared with other bidding methods, the contractor's profit will be greatly reduced, and the contractor's ability to resist natural risks will be weakened, thus increasing the use risk of this bidding method.

3. Risk control of sealed bidding for construction projects

3. 1. The basic characteristics and characteristics of risk determine the feasibility of risk prevention.

There are many ways to prevent risks, but they can be summarized as the following two basic methods: the first is to take risk control measures to reduce the expected loss of the tenderer or make this loss more measurable, thus changing the risk. This method includes risk avoidance, loss control, risk separation, risk dispersion and risk transfer. The second is to take financial measures to prevent losses that have been proved to occur frequently in engineering construction, including buying insurance, keeping risks and protecting themselves.

The first basic method is based on the variable characteristics of risk, conforming to the law and guiding correctly, so as to achieve the ideal effect. Things in the world are ever-changing, and the change of anything can not be separated from internal and external factors and their combination. Changes in internal and external causes will lead to a result; The external cause remains unchanged, but the internal cause has changed, which may lead to another result; The results of internal and external changes on different occasions are naturally different. Changing the risk itself is to take corresponding measures according to this philosophy to obtain beneficial results. Different countermeasures can be taken according to different risks, such as preventing the occurrence of risks, curbing the deterioration of risks, refusing to take risks, avoiding risks, giving up intentions that may lead to risks, etc. It is possible to change the risk itself and reduce the loss, while analyzing the probability of risk occurrence and observing its development trend can achieve the effect of predicting the loss.

Another basic method of risk control is to use economic means, that is, financial countermeasures, to deal with the losses that do occur. These countermeasures include risk transfer, risk retention and self-insurance The so-called risk transfer refers to the risk that the risk transferer seeks compensation and foreign funds actually occur or have occurred. Risk transfer includes insurance risk financial transfer (that is, through insurance transfer) and non-insurance risk financial transfer (that is, through contract terms transfer). The financial transfer of insurance risk is realized by purchasing insurance, and the financial transfer of non-insurance risk is either issued by the guarantee bank or insurance company or by risk neutralization. Risk neutralization is the main process of balancing losses and profit opportunities. For example, the contractor is worried about the change of raw material prices and carries out hedging transactions (ordering at the agreed price in advance and paying according to normal procedures); Exporters are worried about the fluctuation of foreign exchange rate and conduct futures trading. However, there is no chance to benefit from pure risk through risk neutralization. So this means is just a kind of self-defense, which can only ensure that you are not subject to risk loss. Risk retention means that the risk is reserved for yourself and will not be transferred; Risk self-insurance refers to the establishment of an insurance mechanism or an insurance institution within an enterprise.

3.2. The main risk management methods commonly used in construction projects at home and abroad: engineering insurance and engineering guarantee.

In the process of construction project implementation, there are many uncertain factors, both artificial and natural. These uncertain factors are called engineering risks in construction projects. It is called project risk management to transform all kinds of uncertain factors into predictable, preventable, controllable and solvable certainty. There are two methods of project risk management, one is project insurance and the other is project guarantee. Engineering insurance is a common engineering risk management measure in the world. In China's construction projects, engineering insurance was popularized earlier. In addition, insurance has been closely related to people's lives in daily life. Individuals have various types of insurance, such as social insurance, medical insurance, health insurance and life insurance. The concept of insurance has been deeply rooted in people's thoughts and has become a basic concept. Similarly, engineering insurance has been generally recognized in the engineering construction industry and achieved remarkable results. Engineering insurance has become a general means of engineering risk management. Engineering guarantee originated in the United States in the world and was soon accepted by other developed market economy countries or regions. It is a relatively new project risk management method, which is specially aimed at the risk control of sealed bidding for construction projects. China's implementation is late, and people's understanding of its functions is not clear enough. The Ministry of Construction held the first national seminar on engineering guarantee in June 65438+February, 1999. Shenzhen started the pilot project in 2000, and gained rich practical experience, which laid a solid foundation for the comprehensive popularization and application of this method in the country in the future. From the previous analysis of the risks of bidding for construction projects, it can be seen that the risks of bidders are mainly caused by the failure to effectively monopolize the construction project trading market, including speculation, collusion, adverse selection and moral hazard afterwards. These risks are difficult to make up for because of the defects of the construction project trading market itself. Introducing a third-party guarantor into the project guarantee method will make up for this risk to some extent. First, because the guarantor's solvency and credit level are the guarantee; Second, the guarantor will supervise the behavior of both parties in a fair and just way; Third, after signing this kind of project guarantee, it has a great deterrent effect on reducing the adverse selection behavior of bidders and avoiding moral hazard.

3.3. Comparison between engineering insurance and engineering guarantee

Although both engineering insurance and engineering guarantee have the function of controlling engineering dedication, there are still important differences between them:

(1) The number of participants is different. Engineering insurance only involves the direct signing of agreements by both parties, contractors and insurance companies. The project guarantee involves three parties, and the owner signs an agreement with the contractor through the guarantee company.

(2) The stakeholders of the guarantee are different. Engineering insurance is insured by the insured in order to protect the interests of himself or the insured. Project guarantee means that the contractor provides project guarantee at the request of the owner to protect the interests of the owner.

(3) The types of risks insured are different. Engineering insurance covers natural risks and bears unexpected risks beyond the control of the contractor. However, the project guarantee covers man-made risks and bears the credit responsibility of the contractor.

(4) Guarantors have different responsibilities. In engineering insurance, the insurance company bears the economic losses caused by the contractor or natural risks, and only needs to pay the corresponding compensation, and does not have to bear other responsibilities. In engineering guarantee, the guarantee company first undertakes the contractor's performance responsibility, and then bears the economic losses caused by its breach of contract.

(5) The mechanism is different. The mechanism of engineering insurance is to share the risk and loss of a company with everyone through the insurance company. Its essence is an economic compensation mechanism, which has the function of transferring, dispersing and digesting the risks of contractors. The mechanism of engineering guarantee is to return the loss of default risk to the contractor who caused the risk through the intermediary guarantee company. Its essence is a risk reward and penalty mechanism for breach of contract, which has the functions of strengthening the contractor's risk and preventing the owner's risk.

(6) Different thinking positions. Engineering insurance is based on "compensation", and insurance companies pay attention to the problem of more compensation and less compensation to minimize compensation. The project guarantee is based on "no compensation", and the focus is on what measures can be taken to realize no compensation and how to recover compensation from the contractor in the case of compensation.

(7) The nature of premium is different. In engineering insurance, the premium paid by the contractor is used for protection purposes and generally cannot be returned. However, the guarantee fee paid by the contractor in the project guarantee is only equivalent to the handling fee and will not be refunded. In addition, the letter of guarantee is provided for guarantee purposes.

(8) The risk transfer subjects are different. Engineering insurance is the real transfer of contractors' natural risks, and contractors are really insured when they buy insurance. The project guarantee has realized the risk transfer of the owner, but the contractor's default risk has not been transferred, and the contractor has increased the default risk after purchasing the guarantee.

4. Risks of bidders in construction projects and their control.

4. 1, risk preference type of bidders for construction projects

The risks caused by the defects of market structure or construction conditions, human factors, economic factors, political factors and social factors mainly include: the risk of bidders' speculation, the risk of bidders' collusion (including collusion between bidders and individual staff of the tenderee), the risk of bidders' adverse selection and moral hazard, the risk of bidding failure and the risk of uncertain factors in the project. The bidder's response to these uncertain risks depends on his preference for risks. Generally speaking, people's preference for risk can be divided into three types: some people don't care about risk, and these people are called risk neutral; Some people like adventure, and this kind of person is called adventure type; Others avoid risks. These people are called risk averse. Our survey results show that the attitude of contractors (bidders) towards the risks of construction projects basically conforms to three categories, in which most bidders consider themselves risk-neutral, while relatively few people consider themselves risk-seeking and risk-avoiding. Among the contractors who pursue and avoid risks, different contractors have different degrees of risk pursuit and avoidance, with less risk pursuit and less risk avoidance. Therefore, when studying the risk of sealed bidding for construction projects, an important aspect we must seriously consider is the bidder's risk attitude, which will become one of the important factors affecting the bidder's final choice of quotation. The influence of risk on the decision-making of bidders depends on the bidder's attitude towards risk. Obviously, in the face of the same subject matter of the bidding project, bidders will make different quotations with different risk preferences. Our statistical results of the contractor questionnaire just illustrate this problem. 63.3% of the contractors surveyed believe that the quotation of risk-seeking bidders is lower than that of risk-neutral bidders, while that of risk-neutral bidders is lower than that of risk-averse bidders. 78.9% of the contractors choose the lowest risk bidder.

Most foreign bidding and auction theories assume that all bidders are neutral or risk averse with the same risk preference type. The actual situation of China's construction project trading market is just the opposite. At the same time, there are several bidders with different risk preferences, and their quotations will be affected by the different risk preferences of bidders. In this scenario, which bidder with risk preference will bring greater risks to the tenderee when winning the bid? Our questionnaire survey results show that 83.3% of the contractors think that winning the bid by risky bidders will bring risks to the tenderee, while only 6.7% and 10% of the contractors think that winning the bid by risk-neutral and risk-averse bidders will bring risks to the tenderee. The risk attitude of bidders is also very important to the risk study of sealed bidding method. Most literatures on bidding and auction theory assume that the tenderer or auctioneer is risk-neutral or risk-averse. Bidding for construction projects has its particularity. In fact, it is different from bidders who only care about the construction stage. The tenderer pays more attention to the overall benefit after the project is completed and put into use. Construction projects have huge investment and long payback time. Rational and intelligent bidders will not bear the risk of losing more benefits in the future in order to save a little investment in the construction stage, which is determined by the inherent characteristics of construction projects. In addition, the basic national conditions of China also have an impact on the risk behavior orientation of tenderers. The investment system and management system of China's construction projects are characterized by the fact that the project investment and income are owned by the government or units. However, according to the provisions of the project lifelong responsibility system, if there are major quality problems in the construction period or operation period of the construction project, the risk liability shall be borne by the project legal person and the relevant personnel responsible for the construction. The property rights, income rights and risk takers of foreign construction projects are integrated, but in China, the property rights and income rights of construction projects are separated from the actual risk takers. Due to the above reasons, in reality, the attitude of bidders of public projects in China should mainly be risk avoidance, followed by risk neutrality, and few people show risk pursuit. Therefore, we assume that the bidder's risk preference is risk aversion, which is in line with the actual situation of most public works bidding in China.

4.2, the bidder's default punishment mechanism to prevent the risk of sealed bidding method:

Empirical analysis shows that the risk of bidding mainly comes from the risk behavior of bidders. If the bidder's risk behavior is controlled, the bidding method can be effectively controlled from the bidder's human risk. There are many ways to prevent risks. At present, in order to strengthen the management of the construction project trading process, China has formulated some relevant laws and regulations, which clearly stipulate that all kinds of violations in the construction project trading market will be punished. As a means of government control, punishment will have much impact on bidders' bidding behavior and what role it can play in risk control of sealed bidding for construction projects.

With the support of AA Construction Bureau, we collected the construction enterprises in this city (including construction enterprises in this city and construction enterprises registered in this city from other places, as well as state-owned enterprises, joint-stock enterprises and private enterprises with different enterprise qualification levels), conducted a questionnaire survey on the bidding behavior of contractors under different default fines (different penalty ratios and budgeted project profits), * * * distributed 500 questionnaires, and finally got 90 effective feedback questionnaires. It can be found that:

First, vertically, when the ratio of liquidated damages to budgeted project profits is 20%, the contractor's bidding behavior is similar to that of contractors under normal circumstances, and the majority of contractors adopt normal bidding behavior (risk neutrality) (68.9%). The number of contractors with higher bid (risk aversion) and lower bid (risk preference) is 16.7% and 12.2% respectively, and the number of contractors with very high bid (risk aversion) and very low bid (risk preference) is 1. 1% and 6544/%respectively. It shows that when the punishment is light, the punishment has little influence on the contractor's bidding behavior. When the proportion of liquidated damages to the budgeted project profit increased to 50% and 100%, the bidding behavior of each contractor changed greatly, and the proportion of contractors who used normal bidding decreased to 5 1. 1% and 40% respectively. However, the number of contractors who bid very high (very risk-averse) increased to11%and 23.3% respectively, while the number of contractors who bid very low (very risk-averse) decreased to 1. 1% and 0.0% respectively. However, the number of contractors is still less than the normal quotation. At the same time, the number of contractors with relatively low quotations decreased to 10% and 7.8% respectively, which shows that when the punishment intensity increases to a certain extent, the number of contractors who like adventure behavior is greatly reduced, while the number of contractors who hate adventure behavior is greatly increased, which is in line with people's psychological state of being generally afraid of punishing and seeking advantages and avoiding disadvantages. When the ratio of liquidated damages to budgeted project profit is 200% and 500%, the number of contractors with very high bid price increases obviously, which exceeds the number of contractors quoted in normal valuation. The number of contractors with lower bid prices also decreased significantly, but the number of contractors with very high bid prices increased from 0.0% to 2.2% and 4.4% respectively.

Secondly, from a horizontal perspective, the number of contractors corresponding to different liquidated damages also shows some regular differences in bidding behavior: the number of contractors with normal pricing and quotation decreases with the increase of the proportion of liquidated damages in the budget project profits, while the number of contractors with very high bidding price increases with the increase of the proportion of liquidated damages in the budget project profits. With the increase of the ratio of fines to budgeted profits, the number of contractors with low bid prices first decreased and then increased.

5. Concluding remarks

Starting from the connotation of risks and the general characteristics of construction project risks, this paper analyzes several risks and their causes of sealed bidding for construction projects, and probes into the feasibility of risk control and prevention according to their risk characteristics. This paper compares the similarities and differences and advantages between the new project risk management method of project guarantee and the common project risk management method of project insurance. It is considered that one of the important functions of project guarantee is to ensure the smooth implementation of sealed bidding and reduce the project cost. Based on the fact that policyholders have different risk preferences in real life, this paper analyzes the bidding behavior characteristics of policyholders with different risk preferences when faced with different standards of liquidated damages for breach of contract, and draws the conclusion that the risk preference behavior characteristics of bidders change with the change of external environment. When the penalty is light, the bidder tends to pursue risks, but when the penalty standard is raised above a certain value, the bidder's risk behavior changes to tend to avoid risks, and the greater the penalty standard, the more inclined the bidder is to avoid risks. The significance of this theoretical analysis is that it shows that the risk behavior of bidders can be changed by changing the trading market environment in which they live, thus providing an important theoretical basis for us to control and prevent the risk behavior of bidders.