📚 Monopsony in the Labour Market | 劳动市场中的买方垄断
In many labour markets, employers do not simply accept the market wage as given. When a single firm, or a small group of firms, dominates the demand for labour in a particular area or industry, it gains the power to set wages below the competitive level. This situation, known as a monopsony, produces outcomes that differ sharply from those in perfectly competitive labour markets. Understanding monopsony is essential for analysing real-world issues such as wage inequality, the effects of minimum wages, and the role of trade unions.
在许多劳动市场中，雇主并非被动地接受既定的市场工资。当某一家企业或少数几家企业在某个地区或行业中主导了劳动需求时，它就获得了将工资压低到竞争水平以下的能力。这种情况被称为买方垄断，它产生的后果与完全竞争劳动市场截然不同。理解买方垄断对于分析工资不平等、最低工资的影响以及工会角色等现实问题至关重要。
1. Definition of Monopsony | 买方垄断的定义
A monopsony is a market structure in which there is only one buyer for a particular good, service or factor of production. In the context of the labour market, a monopsony exists when there is a single dominant employer, or a collusive group of employers, who face the entire market supply of labour for that occupation or region.
买方垄断是指某一特定商品、服务或生产要素只有一个买方的市场结构。在劳动市场的语境下，当某一个主导性雇主，或者合谋的雇主集团，面对某个职业或地区全部的劳动供给时，便形成了买方垄断。
Monopsony power can also arise in situations where a few large firms dominate employment, known as an oligopsony. The key feature is that the employer is a wage maker rather than a wage taker, meaning its hiring decisions directly influence the wage rate it must pay. This contrasts with perfect competition, where each firm is so small that it can hire as many workers as it wishes at the going market wage.
当少数几家大企业主导就业时，也会产生买方垄断权力，这种情况称为寡头买方垄断。其关键特征是雇主是工资制定者而非工资接受者，这意味着它的雇佣决策直接影响它必须支付的工资率。这与完全竞争不同，在完全竞争条件下，每家企业规模都很小，可以以现行市场工资雇佣任意数量的工人。
2. Key Characteristics of a Monopsony Employer | 买方垄断雇主的关键特征
A monopsonistic labour market typically exhibits several distinct characteristics. First, there is a single large employer or a highly concentrated group of employers that dominate the hiring of a specific type of labour. Workers have few alternative employment opportunities, which gives the employer significant bargaining power.
买方垄断的劳动市场通常具有几个显著特征。首先，存在一个大型雇主或高度集中的雇主集团，主导着某一特定类型劳动的雇佣。工人几乎没有其他就业选择，这使得雇主拥有很强的议价能力。
Second, there are barriers to labour mobility that prevent workers from easily seeking jobs elsewhere. These barriers can be geographical, such as when a company is the only major employer in a remote town, or occupational, where specialised skills are not easily transferable to other industries.
其次，存在阻碍劳动力流动的壁垒，使工人无法轻易到别处寻找工作。这些壁垒可能是地理上的，例如某家公司是偏远城镇唯一的主要雇主；也可能来自职业层面，即专业技能不容易转移到其他行业。
Third, the employer is a wage maker rather than a wage taker. To attract additional workers, the firm must raise the wage it offers, not only for the new employee but often for all existing workers doing similar jobs. This creates an upward-sloping labour supply curve faced by the firm, and the marginal cost of labour exceeds the wage rate.
第三，雇主是工资制定者而非工资接受者。为了吸引更多工人，该企业必须提高其提供的工资，这不仅适用于新雇员，通常也适用于从事类似工作的所有现有工人。这使得企业面临的劳动供给曲线向上倾斜，且边际劳动成本超过工资率。
3. The Labour Supply Curve Facing a Monopsonist | 买方垄断者面临的劳动供给曲线
In a perfectly competitive labour market, an individual firm faces a horizontal, perfectly elastic labour supply curve at the market wage. It can hire any number of workers without affecting the wage. In a monopsony, however, the firm represents the entire market demand for labour, so it must accept the market supply curve, which is upward sloping.
在完全竞争的劳动市场中，单个企业面对的是在市场工资水平上呈水平线、完全弹性的劳动供给曲线。它可以雇佣任意数量的工人而不影响工资水平。然而在买方垄断中，企业代表了整个市场的劳动需求，因此它必须接受市场供给曲线，这条曲线是向上倾斜的。
The upward-sloping labour supply curve means that if a monopsonist wants to employ more workers, it must offer a higher wage to attract them from alternative uses of time, such as leisure, household work, or other regions. Because the higher wage typically has to be paid to all workers, the extra cost of hiring one more worker, the marginal cost of labour (MCL), rises faster than the wage.
向上倾斜的劳动供给曲线意味着，如果买方垄断者想要雇佣更多的工人，就必须提供更高的工资，以将他们从时间的其他用途（如休闲、家务或其他地区）中吸引过来。由于更高的工资通常要支付给所有工人，因此每多雇一个工人的额外成本，即边际劳动成本（MCL），会比工资上升得更快。
of labour is MCL = a + 2bL. The slope of the MCL curve is twice as steep as the supply curve, a geometric relationship that is crucial for understanding the monopsony equilibrium.
对于形如 W = a + bL 的线性供给曲线（其中 W 为工资，L 为劳动数量），总工资支出为 WL = aL + bL²，边际劳动成本则为 MCL = a + 2bL。MCL 曲线的斜率是供给曲线的两倍，这一几何关系对于理解买方垄断均衡至关重要。
4. Marginal Cost of Labour (MCL) | 边际劳动成本 (MCL)
The marginal cost of labour is the additional total cost a firm incurs when it hires one more unit of labour. In perfect competition, MCL equals the market wage, because hiring one extra worker does not change the wage paid to others. Under monopsony, however, the MCL lies above the labour supply curve at every level of employment.
边际劳动成本是指企业每多雇用一单位劳动所增加的总成本。在完全竞争中，MCL 等于市场工资，因为多雇一个工人不会改变支付给其他人的工资。然而在买方垄断下，MCL 在每个就业水平上都高于劳动供给曲线。
This occurs because the monopsonist must raise the wage for all workers when it wishes to employ more. The gap between MCL and the supply curve reflects the extra cost of raising the wage for inframarginal workers. As a result, the profit-maximising monopsonist will restrict employment to the point where the marginal revenue product of labour (MRPL) equals MCL, rather than where MRPL equals the wage.
这是因为买方垄断者在希望雇佣更多工人时，必须为所有工人提高工资。MCL 与供给曲线之间的差距反映了为超边际工人提高工资所带来的额外成本。因此，追求利润最大化的买方垄断者会将就业限制在劳动的边际收益产品（MRPL）等于 MCL 的点上，而非 MRPL 等于工资的点上。
The marginal revenue product of labour, which represents the additional revenue generated by the last worker hired, declines as employment increases due to the law of diminishing returns. The intersection of the downward-sloping MRPL curve and the steeper MCL curve determines the monopsony employment level.
劳动的边际收益产品代表着最后雇佣的工人所产生的额外收益，由于收益递减规律，它随就业增加而下降。向下倾斜的 MRPL 曲线与更陡峭的 MCL 曲线的交点决定了买方垄断的就业水平。
5. Profit Maximisation: Employment and Wage Determination | 利润最大化：就业与工资决定
l, the firm then looks down to the labour supply curve to determine the wage it must pay to attract exactly that number of workers. Because the supply curve lies below the MCL curve, the wage paid, Wm, is lower than both the MCL and the MRPL at that employment level.
一个追求利润最大化的买方垄断者会雇佣工人直到 MRPL = MCL 的产量水平。在这一就业水平上，企业再向下看劳动供给曲线，来确定要吸引这么多工人必须支付的工资。由于供给曲线位于 MCL 曲线下方，所支付的工资 Wm 低于该就业水平上的 MCL 和 MRPL。
This means the monopsonist extracts a surplus from workers, who are paid less than the value of their marginal contribution to the firm's revenue. Compared with a perfectly competitive labour market, the monopsony outcome features both lower employment and a lower wage. The monopsonist's exploitation of workers is a direct consequence of its market power.
这意味着买方垄断者从工人身上榨取了剩余，工人所获报酬低于他们对企业收入边际贡献的价值。与完全竞争劳动市场相比，买方垄断的结果是就业更低、工资更低。买方垄断者对工人的剥削是其市场力量的直接后果。
In a diagram, employment is read off the horizontal axis at the intersection of MRPL and MCL, and the wage is found by dropping a vertical line from that point down to the labour supply curve. This well-known 'monopsony markup' over the wage illustrates the wage gap that can persist without corrective intervention.
在图形中，从 MRPL 和 MCL 的交点向横轴读出就业量，然后从该点向下画一条垂直线到劳动供给曲线上，即可找到工资。这种众所周知的“买方垄断加成”高于工资，说明了在没有纠正性干预的情况下可能持续存在的工资差距。
6. Comparing Monopsony with Perfect Competition | 买方垄断与完全竞争的比较
A side-by-side comparison highlights the inefficiencies generated by monopsony power in the labour market. Under perfect competition, the equilibrium occurs where labour demand (reflecting MRPL) equals labour supply, and the wage equals both. Under monopsony, equilibrium is where MRPL equals MCL, yielding lower employment and a wage below MRPL.
并列比较可以凸显劳动市场中买方垄断权力所造成的低效率。在完全竞争下，均衡出现在劳动需求（反映 MRPL）等于劳动供给之处，且工资等于二者。在买方垄断下，均衡出现在 MRPL 等于 MCL 之处，导致就业减少、工资低于 MRPL。
| Feature | 特征 | Perfect Competition | 完全竞争 | Monopsony | 买方垄断 |
|---|---|---|
| Wage determination | 工资决定 | Wage = MRPL (Wc) | 工资 = MRPL (Wc) | Wage < MRPL (Wm) | 工资 < MRPL (Wm) |
| Employment level | 就业水平 | Lc (higher) | Lc (更高) | Lm (lower) | Lm (更低) |
| MCL vs. Wage | MCL 与工资 | MCL = Wage | MCL = 工资 | MCL > Wage | MCL > 工资 |
| Worker surplus | 工人剩余 | Maximised | 最大化 | Reduced; deadweight loss | 减少；产生无谓损失 |
The table shows that monopsony not only depresses wages but also reduces the total number of workers employed. The labour market fails to allocate resources efficiently because the value of the last worker employed is higher than the wage, meaning there are willing workers and profitable opportunities that are not being matched.
该表显示，买方垄断不仅压低工资，还减少了总就业人数。劳动市场未能有效配置资源，因为最后雇佣的工人所创造的价值高于工资，这意味着存在有意愿的工人和有利可图的机会，却未能实现匹配。
7. Welfare Effects and Deadweight Loss | 福利效应与无谓损失
The monopsony outcome leads to a loss of economic welfare. In a competitive labour market, the sum of employer surplus and worker surplus is maximised at the equilibrium. Under monopsony, employment is restricted to Lm, which is below the competitive level Lc. This constriction creates a deadweight loss, as there are mutually beneficial trades that do not take place.
买方垄断的结果导致经济福利的损失。在竞争性劳动市场中，雇主剩余与工人剩余之和在均衡点达到最大化。在买方垄断下，就业被限制在低于竞争水平 Lc 的 Lm。这种缩减造成了无谓损失，因为有些对双方都有利的交易并未发生。
The deadweight loss can be visualised on the standard diagram as the triangle between the MRPL curve and the labour supply curve, to the right of the monopsony employment level Lm and up to the competitive employment level Lc. This area represents the net benefits forgone. Moreover, monopsony redistributes surplus away from workers to the employer, increasing inequality.
在标准图形中，无谓损失可以表示为 MRPL 曲线与劳动供给曲线之间的三角形区域，位于买方垄断就业水平 Lm 的右侧、直至竞争就业水平 Lc。该区域代表了被放弃的净收益。此外，买方垄断将剩余从工人手中重新分配给雇主，加剧了不平等。
Because workers are paid less than their MRPL, the monopsonist captures a larger share of the economic pie. This has implications for both allocative efficiency and equity. The labour market on its own cannot correct this inefficiency, providing a rationale for government intervention.
由于工人获得的报酬低于其 MRPL，买方垄断者攫取了经济蛋糕中的更大份额。这对配置效率和公平均有影响。劳动市场本身无法纠正这种低效率，这为政府干预提供了依据。
8. The Impact of a Minimum Wage in a Monopsony | 最低工资对买方垄断的影响
In a perfectly competitive labour market, a minimum wage set above the equilibrium creates unemployment. However, in a monopsony, a carefully set minimum wage can simultaneously raise wages and increase employment, up to a point. This surprising result occurs because the minimum wage limits the monopsonist's ability to drive down the wage by restricting hiring.
在完全竞争的劳动市场中，设定在均衡水平之上的最低工资会造成失业。然而，在买方垄断中，一个精心设定的最低工资可以在一定范围内既提高工资又增加就业。这一令人惊讶的结论之所以成立，是因为最低工资限制了买方垄断者通过限制雇佣来压低工资的能力。
When a minimum wage is imposed between the monopsony wage Wm and the competitive wage Wc, the firm's MCL curve becomes horizontal at the level of the minimum wage up to the quantity of labour supplied at that wage. The new profit-maximising employment level rises to where the minimum wage (now the effective MCL) equals MRPL. This can raise employment from Lm towards Lc, reducing deadweight loss.
当最低工资设定在买方垄断工资 Wm 与竞争工资 Wc 之间时，企业的 MCL 曲线在最低工资水平上变成一条水平线，一直延伸到该工资水平下的劳动供给量。新的利润最大化就业水平上升到最低工资（此时即有效的 MCL）等于 MRPL 之处。这可以将就业从 Lm 提高到接近 Lc 的水平，从而减少无谓损失。
If the minimum wage is set too high, however, beyond the competitive wage Wc, employment will fall below the original monopsony level, potentially causing unemployment. This non-linear relationship is a key policy insight: under monopsony, minimum wages can be a corrective tool, but their effectiveness depends on careful calibration.
然而，如果最低工资设定得过高，超过了竞争工资 Wc，就业就会下降到低于原来的买方垄断水平，可能引发失业。这种非线性关系是一项重要的政策洞见：在买方垄断下，最低工资可以成为一种纠正工具，但其效力取决于精准的校准。
9. The Role of Trade Unions | 工会的角色
In a monopsonistic labour market, trade unions can act as a countervailing power to the dominant employer. By organising workers and bargaining collectively, a union can raise the wage above the monopsony level without necessarily reducing employment, provided the negotiated wage stays within the range between Wm and the competitive wage.
在买方垄断的劳动市场中，工会可以充当对主导性雇主的抗衡力量。通过组织工人并进行集体谈判，工会可以将工资提高到买方垄断水平之上，而不一定减少就业——前提是谈判的工资维持在 Wm 与竞争工资之间的范围内。
Unions can also bargain over non-wage aspects such as job security, working conditions and training, which may improve labour market outcomes more broadly. However, if union power is too strong and pushes the wage significantly above the competitive level, employment can fall below the monopsony quantity, recreating some of the inefficiencies seen under an excessively high minimum wage.
工会还可以就非工资方面进行谈判，如工作保障、工作条件和培训，这些可能更广泛地改善劳动市场结果。但是，如果工会力量过强，将工资推高到显著高于竞争水平的位置，就业就会下降到低于买方垄断的数量，从而重现最低工资过高时的某些低效率。
In many sectors with some degree of monopsony power, the presence of trade unions and collective bargaining frameworks can help move the labour market closer to a competitive equilibrium, improving both equity and efficiency. This is a reason why several governments actively support sectoral bargaining in industries where employer concentration is high.
在具有一定程度买方垄断权力的许多行业中，工会和集体谈判框架的存在有助于使劳动市场更接近竞争均衡，从而改善公平与效率。这也是为何一些政府积极支持雇主集中度较高行业的行业性谈判的原因之一。
10. Evaluation and Real-World Applications | 评价与现实应用
While the pure monopsony model offers clear predictions, real labour markets are rarely characterised by a single employer. Instead, oligopsony, where a few large firms dominate hiring, is more common. Even in such cases, each firm may have some monopsony power, especially if workers face switching costs, imperfect information or geographical immobility.
尽管纯粹的买方垄断模型提供了清晰的预测，但现实劳动市场极少由单一雇主构成。更常见的是寡头买方垄断，即少数几家大企业主导雇佣。即使如此，每家企业都可能拥有一定的买方垄断权力，尤其当工人面临转换成本、信息不完全或地理流动性受限时。
Examples often cited include company towns, where a single mining or manufacturing firm is the only significant employer, or national health services that act as the near-exclusive employer of nurses and doctors. More recent research suggests that labour market concentration in many industries, from retail to tech, gives large firms monopsonistic power even in urban areas, contributing to stagnant wages despite rising productivity.
常被引用的例子包括公司镇，那里的单一采矿或制造企业是唯一重要的雇主，或者国家医疗服务体系几乎是护士和医生的独家雇主。近期的研究表明，从零售业到科技业，许多行业的劳动市场集中度赋予了大型企业买方垄断权力，即使在城市地区也是如此，从而在生产率上升的情况下导致了工资停滞。
In evaluating the model, economists note that monopsony power is not always harmful in a static sense if it enables firms to invest in worker training, as they can recoup the costs. However, the distributional consequences and the potential for wage suppression remain important concerns for policymakers. Instruments such as minimum wages, trade union recognition, and competition policy in labour markets are all part of the policy toolkit for addressing monopsony power.
在评价这一模型时，经济学家指出，如果买方垄断权力使企业能够投资于工人培训并回收成本，那么从静态角度看，它不一定有害。然而，分配后果和工资压制的可能性仍然是政策制定者关注的重要问题。最低工资、工会认可以及劳动市场的竞争政策等工具，都是应对买方垄断权力政策工具箱的一部分。
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