Thesis (M.Sc. Agriculture (Agricultural Economics)) -- University of Limpopo, 2021 / Raising cattle in South Africa and any other developing country in the Southern African region as part of livestock production, is one of the important means through which people sustain their livelihood. Inadequate efforts have been taken by the government to improve the marketing system of cattle, particularly to develop small-scale farming in the Limpopo Province and South Africa as a whole. With that being said, the small-scale sector has not been developed to the extent it is expected to. This study examined the factors affecting the participation of small-scale cattle farmers in livestock auctions in the Capricorn District of the Limpopo Province. The study had three objectives, namely; (i) To describe the socio-economic characteristics of the small scale cattle farmers in the Capricorn District of the Limpopo Province; (ii) To assess the perception of small-scale cattle farmers in the Capricorn District of the Limpopo Province towards livestock auction; (iii) To identify and analyse factors affecting the participation of small-scale cattle farmers in livestock auctions in the Capricorn District of the Limpopo Province. The Multi-stage sampling procedure was used in the selection of the representative sample. Three locations (Lepelle-Nkumpi, Molemole and Polokwane local municipalities) were selected purposively because a large number of small-scale cattle farmers in the Capricorn District rely on the agricultural sector economically. The Logistic Regression Model was used to analyse factors affecting the participation of small-scale cattle farmers in livestock auctions. The results showed that, out of the 120 sample size, 42% of small-scale cattle farmers were auction participants and 58% of small-scale cattle farmers were non-participants . There were 43 male-headed households of the participants and 61 female-headed households of the non-participants . An analysis of the farmers ’ socio-economic characteristics further showed that in order for the farmers to cut the costs of production, the majority of the small-scale cattle farmers preferred using family labourers or household labourers in their cattle farming. Farmers were asked a set of Likert type scale questions about their perceptions on the auctions. The Perception Index score ii was skewed to the left and therefore revealed that the small-scale cattle farmers had a negative perception towards the auction. Farmers who had a positive perception, on the other hand, often sold their cattle at a higher price compared to the non-participants who had a negative perception. Furthermore, small-scale cattle farmers who are participants tend to use the market avenue and through that, their cattle productivity is higher, resulting in a total revenue compared to the non-participants. Consequently, small-scale farmers who participate in auctions acquire valuable production information at the very auctions. Descriptive statistics such as means, minimum and maximum values, frequencies, percentages and standard deviations were used to describe the socioeconomic characteristics of the small-scale cattle farmers in the Capricorn District of the Limpopo Province. The results revealed that only 4 variables were significant. The total herd size, distance to the market, gender of the household head and market information were significant at 1%, 5%, 1%, 5%, respectively and all had a positive effect towards auction participation. The study suggested that the government and other policy makers should increase the marketing information and abilities of small-scale cattle farmers through avenues like mass media, extension service and other means of capacity building. This will help the farmers to minimise transaction costs. Furthermore, farmers will not incur more costs when they participate in the markets, considering that market facilities such as auctions are often hosted far from the farmers, which results in farmers incurring more costs.

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[pt] Nesse artigo, estudamos os leilões de petróleo e gás no Brasil para medir o impacto de requerimentos de conteúdo local nos lances realizados, o que nos permite estimar o seu impacto na receita obtida pelo governo. O caso brasileiro é particularmente atrativo, uma vez que houve variação significativa das exigências de conteúdo local ao longo do anos. Nas rodadas em que os requerimentos foram mais altos, observamos uma mudança significativa no comportamento dos participantes dos leilões: o bônus de assinatura médio em blocos offshore caiu de uma média de 57 milhões de reais nas primeiras rodadas para apenas 10,6 milhões de reais, e o número médio de lances por bloco caiu de 0,92 para 0,12. Nosso objetivo é responder em que medida a elevação das exigências de conteúdo local afetaram participação e receita nos leilões. Nós desenvolvemos e estimamos um modelo estrutural de leilões dentro do arcabouço de valores comuns que inclui a decisão de entrada e lances em múltiplas dimensões, incluindo um bônus e um percentual de conteúdo local. Nossos resultados mostram que as exigências de conteúdo local elevam os custos em blocos em águas profundas em 14 por cento. A receita governamental em leilões nessas áreas poderia ser muito maior em um contrafactual sem exigências de conteúdo local, contabilizando 17 bilhões de reais em receita de bônus de assinatura apenas em águas profundas. Em blocos em terra, não encontramos diferenças significativas de custo local e estrangeiro. / [en] In this paper, we study the case of Brazilian oil and gas auctions to assess the impact of local content requirements in bidding behavior, allowing us to estimate its impact on government revenue. The Brazilian case is particularly appealing, as there were significant changes in these requirements throughout the years. In the sales with increased local content requirements there was a dramatic change in the bidders behavior: the average signing bonus for offshore tracts dropped from an average of 57 million reais in the first sales to only 10.6 million reais and the average number of bids per tract plunged from 0.92 to 0.12. We aim to answer how much the increased local content requirements affected participation and revenue in the auctions. We develop and estimate a structural auction model within the mineral rights framework that includes an entry decision and bids in multiple dimensions, including a bonus and a local content percentage. Our results show that local content requirements increase costs in deep water areas in 14 por cento. Government revenue in auctions in these areas could be much larger in a counterfactual with no local content requirements, amounting to an extra 17 billion reais in signing bonus only for deep-water tracts. For onshore areas, we did not find any significant difference between local and foreign costs.

This thesis comprises four essays in the economics of networks and market design. The common thread in all these essays is the presence of complementarities or externalities. Chapter 2 presents a unified model of networks and matching markets. We build on a contribution by Pycia (2012). We show that strong pairwise alignment of agents’ preferences is a necessary and sufficient condition for the existence of strongly stable networks and strongly stable allocations in multilateral matching markets with finite contracts. Strongly stable networks are not necessarily efficient. Although we use a demanding stability concept, strong pairwise alignment allows for complementarities and externalities. In Chapter 3, we generalise the gross substitutes and complements condition introduced by Sun and Yang (2006). Our new condition guarantees the existence of competitive equilibrium in economies with indivisible goods. Competitive equilibrium can be found using an extension of the double-track adjustment process (Sun and Yang, 2009). In this chapter, we also study contract networks (Ostrovsky, 2008). We show that chain-stable contract allocations can exist even in cyclical contractual networks, such as electricity markets, as long as they are appropriately segmented. In Chapter 4, we run a series of experiments to compare the performance of four auctions – first-price, Vickrey, Vickrey-Nearest Rule (Day and Cramton, 2008), and Reference Rule (Erdil and Klemperer, 2010). In our setting, there are two items and three bidders. Two local bidders want an item each, but the global bidder wants both items. We introduce various exposure and package-bidding treatments. We find that the first-price auction always revenue-dominates all the other auctions without any loss in efficiency, strengthening the results of Marszalec (2011). Exposure affects global bidders only in the first-price auction. In other auctions, global bidders often do not take into account the effect of their own bids on their payments. We find no evidence of threshold effects. Finally, in Chapter 5, we develop a new model of online social network formation. In this model, agents belong to many overlapping social groups. We derive analytical solutions for the macroscopic properties of the network, such as the degree distribution. We study the dynamics of homophily – the tendency of individuals to associate with those similar to themselves. We calibrate our model to Facebook data from ten American colleges.

過去認為賣家評價對於價格是正、統計上顯著地影響價格，但是這影響卻不大，我們建立一個模型去解釋是兩種正負關係互相抵消，造成觀察到的結果是很小的情況。具體的說，賣家需要高評價分數去銷售高單價商品，而累積評價分數快速又低成本的方法就是利用低單價商品，利用降低低單價商品價格，讓銷售量增加的更快，銷售量增加快，評價就會增加快速。所以評價對於低價商品是一種負的關係，對於高單價商品才是正的關係。 / It has been recognized empirically that in internet auctions, seller's reputation has a positive, statistically significant, but small impact on the price. We construct a model on internet auctions and delineate this small impact with two opposite forces. To be specific, it needs higher reputation for sellers to sell high-price goods and a cheap way to achieve this objective is to lower the price of low-price goods. By this way one can raise the sale volume of low-price commodities to increase reputation score quickly, which benefits the sale of high-price goods. Therefore, reputation imposes positive impact on prices of "expensive" goods and negative impact on prices of "cheap" ones.

The existing literature on information disclosure commonly assumes full commitment to truthful disclosure and therefore revelations are always credible, which can be quite unrealistic in many circumstances. This thesis mainly contributes to the literature by studying information disclosure in the form of cheap-talk in auctions and monopoly pricing, which allows for mis-reporting and false disclosure. The thesis is composed mainly of three research papers. The first paper (Chapter 2), also the major chapter of this thesis, investigates cheap-talk information disclosure in auctions, where bidders' preferences are horizontally differentiated. The seller may reveal information of product attributes before the auction, and the disclosure policy is characterized by a partition of the attribute space. In a symmetric setting, I first show that informative equilibria reveal the feature that more precise information is provided for less popular product attributes. Second, I prove an equilibrium existence theorem that an informative equilibrium can be supported by an information partition of any degree, as long as the number of bidders is sufficiently large. And finally, the optimal disclosure policy reveals a complementarity relationship between the number of bidders and the optimal degree of equilibrium partitions. In this chapter, optimal information structure is endogenously determined. In the second paper (Chapter 3), I turn to study how a monopoly seller should reveal a product's horizontal attributes, when consumer preferences conform to a mixture distribution. I show that the optimal disclosure policy largely depends on the characteristics of the mixture distribution. Specifically, when consumer preferences are highly heterogenous, it is better for the seller to reveal information and serve different groups of consumers separately. And when the preference distribution becomes more asymmetric, cheap-talk disclosure is more likely to be dominated by no disclosure at all. In this chapter, information structure is taken as given. The third paper (Chapter 4) studies optimal regulation of risk-averse producers, in a setting of complementary production with independent cost realization. The production can be organized in the form of either component, or integrated production. I show in this paper that the relative virtues of these two forms of production depend on the degree of risk aversion of the producers.

We study the effects of the recent economic crisis on firms' bidding behavior and markups in sealed bid auctions. Using data from Austrian construction procurements, we estimate bidders' construction costs within a private value auction model. We find that markups of all bids submitted decrease by 1.5 percentage points in the recent economic crisis, markups of winning bids decrease by 3.3 percentage points. We also find that without the government stimulus package this decrease would have been larger. These two pieces of evidence point to pro-cyclical markups. (authors' abstract)

One goal of every business is to save money, and building strategies that work to minimize spending and maximize profit is key to the success of a company. Cidewalk is a mobile advertisement company that wished to implement an optimal bidding strategy to help reduce the company's cost and in turn maximize their profits. To accomplish this goal we collected market data which was then analyzed to identify the distribution of second best bids, which is the price Cidewalk pays for an advertisement space by bidding in a Vickrey auction. The optimal bidding model was then implemented through a simulation together with Bayesian updating methods to ensure the model would be responsive to changes in the market. The model's performance was evaluated through the simulation and it was discovered that throughout one day the implemented model yielded 17% savings when compared to Cidewalk's current bidding model.

One goal of every business is to save money, and building strategies that work to minimize spending and maximize profit is key to the success of a company. Cidewalk is a mobile advertisement company that wished to implement an optimal bidding strategy to help reduce the company's cost and in turn maximize their profits. To accomplish this goal we collected market data which was then analyzed to identify the distribution of second best bids, which is the price Cidewalk pays for an advertisement space by bidding in a Vickrey auction. The optimal bidding model was then implemented through a simulation together with Bayesian updating methods to ensure the model would be responsive to changes in the market. The model's performance was evaluated through the simulation and it was discovered that throughout one day the implemented model yielded 17% savings when compared to Cidewalk's current bidding model.

[pt] Este trabalho apresenta um modelo de conluio em leilões repetidos de primeiro preço estático, ou seja, um esquema de conluio que usa a mesma regra de conluio em toda a fase de cooperação, independente da história do superjogo. Neste ambiente, introduzimos um mecanismo de comunicação sem custo, por meio do qual os jogadores transmitem sua ordenação de preferências sobre os bens a serem leiloados no jogo estágio. A partir deste modelo, obtemos um aumento da receita esperada agregada por parte dos participantes do leilão frente a um modelo de conluio estático tácito. Além disso, o resultado de dominância do conluio dinâmico com comunicação - esquema no qual a regra de conluio depende de toda a história pública do superjogo - apresentado por Aoyagi (2002), frente a qualquer conluio estático não se verifica. Outro ponto a se destacar é que o refinamento do sistema de comunicação, por meio de um aumento do número de bens ordenados em cada mensagem, embora leve a um aumento da receita esperada, pode gerar uma elevação da taxa de paciência necessária para a manutenção do conluio. / [en] This paper models a Static Collusion in repeated First Price Auctions, that is, a bid rotation scheme which uses the same instruction rule throughout the collusion phase independent of the history. In this environment, we allow that bidders send cheap talk messages to each other about their ranking of preferences over goods that will be auctioned during the stage game. We can show that the introduction of the cheap talk messages improves the bidder`s aggregated surplus compared to tacit static collusion models. Moreover, the dominance of dynamic bid rotation schemes, as showed by Aoyagi (2002), on static versions is not necessarily truth. Another remark is that refining the cheap talk mechanism, by the extension of ranking chain, although generates larger expected receipts, may increases the minimum necessary patience rate to sustain collusion.