我国鸡蛋价格波动传导的影响因素分析——基于非对称的研究视角

[目的]文章采用鸡蛋价格的周度批发和零售数据,从成本、替代品两个维度探讨鸡蛋价格波动的影响因素和非对称传导特征。[方法]通过滚动回归的方式探讨非对称传导特征的动态变化,并进一步探讨了鸡蛋批零价格之间的相互影响和非对称传导特点。[结果]成本、替代品价格变动对与鸡蛋批零价格具有正向影响和非对称特征,但在静态的线性回归模型中并不明显。鸡蛋批发价格受成本价格变动的影响更大,而零售价格受替代品价格变动的影响更大。在动态的滚动回归模型下,成本、替代品价格对鸡蛋价格波动具有十分明显的时变非对称特征,但这种非对称传导特征并不一致。鸡蛋批发价格早期对零售价格具有正向的非对称传导,但近年来趋向于对称传导。鸡蛋零售价格对批发价格总体具有负向的非对称传导特征,零售价格下降对批发价格的影响更大。[结论]需要建立蛋鸡产业成本—价格监测预警系统,充分发挥产业技术平台、行业协会、学会等研究机构在生产决策中的指导作用。不断完善鸡蛋供应链建设,增强调控与监管政策的灵活性与创新性。     

Price Dynamics in a Vertical Sector: The Case of Butter

We develop a reduced-form model of price transmission in a vertical sector, allowing for refined asymmetric, contemporaneous and lagged, own and cross-price effects under time-varying volatility. The model is used to investigate the wholesale-retail price dynamics in the U.S. butter market. The analysis documents the nature of nonlinear price dynamics in a vertical sector. It finds strong evidence of asymmetric retail price responses, both in the short term and the longer term, but only weak evidence of asymmetric wholesale price responses. Asymmetric retail responses play a major role in generating a skewed distribution of butter prices. The empirical results indicate the presence of imperfect competition at the retail level.     

Price shock transmission: evidence from the wheat‐bread market value chain in Ethiopia

This study assesses the degree of vertical price transmission along the wheat‐bread value chain in Ethiopia. This is pursued by applying a vector error correction model and an impulse response analysis using monthly price data for the period 2000–2015. Our analysis considers transmission of price shocks across different market levels, including from the international and domestic wheat grain markets at the upstream to the domestic wheat bread market at the downstream of the value chain. The empirical findings indicate that significant cointegration exists across prices of the different market stages. There is a transmission from international prices to domestic prices at downstream markets, in particular to flour and bread prices. Prices at upstream markets are largely influenced by the domestic wholesale market. In general, the speed of adjustment is quite slow with a half‐life of about one year for restoring the equilibrium price relationship. As price margins between the different market stages in the value chain have substantially decreased in the last 15 years, higher transmission, and thus exposure to international market shocks, can be expected in the future. The results also show that causal relationships exist between prices at different market stages—with the wholesale market identified as the key market level where prices and price expectations are formed.     

Spatial integration between Finnish and Dutch potato markets

This study estimated a conditional mean model for producer prices of fresh potatoes in Finland and for wholesale selling prices of fresh potatoes in the Netherlands. Unit roots were tested in the Finnish and Dutch price series. Then, an asymmetric error correction model with thresholds was estimated for potato prices between Finland and the Netherlands. Asymmetry was allowed both in short and long-run price transmission. The results suggest that the prices are cointegrated and the arbitrage system is functioning, but with a significant time lag between the Finnish and Dutch potato markets. The price response is also asymmetric in that the Finnish price moves towards a steady state equilibrium faster from above than from below the equilibrium.     

食品安全丑闻报道与产销价格传导——基于中国猪肉市场的经验研究

本文利用主流媒体对猪肉质量安全事件的新闻报道构造食品安全丑闻报道指数,首次从媒体报道视角分析食品安全丑闻对中国猪肉供应链产销价格传导的影响。平滑转换误差修正模型检验结果表明:(1)食品安全丑闻报道是决定产销价格传导关系的门槛变量,当食品安全丑闻报道指数处于门槛值以内时,产销价格传导表现为线性关系,超出门槛值以后,则表现为非线性关系,但更多时候表现为非线性关系;(2)食品安全丑闻报道对产销价格具有非对称冲击效应,生猪价格比猪肉价格对冲击的反应程度更大、持续时间更长。这种非对称冲击效应不仅会打破产销价格波动的固有规律,也会加剧供应链上福利分配不均衡,处于弱势地位的养殖户更容易遭受福利损失。进一步采用向量自回归模型进行脉冲响应分析,结果仍然支持上述结论。     

Price Cycles and Asymmetric Price Transmission in the U.S. Pork Market

Economists have proposed several plausible explanations for observed price transmission asymmetries in commodity markets. Unfortunately, the econometric methods commonly used in such studies cannot empirically distinguish pricing behavior under the competing theories. We argue that the theories may be classified by firm responses to high- and low-frequency price cycles and use Engle's band spectrum regression to test the symmetry of high- and low-frequency cycles in weekly pork prices. The findings indicate that changes in wholesale prices are asymmetrically transmitted to retail prices in relatively low-frequency cycles, which does not support search costs and other high-frequency explanations. Conversely, wholesale pork prices asymmetrically adjust to changes in farm prices at all frequencies.     

Transaction Cost Thresholds in International Rice Markets

Recent episodes of high and volatile prices for grains such as rice have raised concerns about their implications for hunger and poverty. We model price relationships between international rice prices and 221 domestic prices in 47 developing countries that import rice. We use a threshold vector error correction model that accounts for transaction costs of trade in spatial price transmission, and an improved regularised Bayesian threshold estimator for threshold models. Our results show that threshold values are higher after 2008 than before, which suggests that transaction costs in international rice trade have increased in recent years. Threshold values are highest for Latin American countries followed by African and Asian countries, and higher for retail than for wholesale prices. Since 2008, price transmission is slower in countries that responded to high and volatile prices with domestic market‐based interventions such as price controls and faster in countries that responded by lowering tariffs and by implementing production support measures.     

Farm-gate tomato price negotiations under asymmetric information

This article provides an empirical analysis of farm‐gate tomato price negotiations under asymmetric information. Regression models are estimated to analyze when and by how much sellers stick to their initial ask prices and what explains the variation in the initial ask–offer price spread. Detailed information on 66 farm‐gate tomato transactions and daily tomato wholesale price data from the central vegetable market in Addis Ababa are used for the analysis. Estimation results show that farmers are less committed to their initial ask price when the buyer speaks out the transaction price first, when their quality perceptions of the tomatoes being transacted differ from those of the buyers, and when their tomato farm is at a large distance from the main road. Sellers stick more to their initial ask price when they know that the central market price is high. The initial ask–offer price spread decreases when the buyer speaks out the initial negotiation price first, but increases in the difference in quality perception between buyer and seller, and in the quantity of tomatoes being transacted.     

Vertical price transmission in timber and lumber markets

Timber and lumber markets are linked and integrated through prices at several stages along timber supply chain. In this study, the degree of vertical integration and the presence of asymmetric price transmission are investigated for sawtimber and lumber products in the southern and western United States. The data utilized are quarterly stumpage price, delivered timber price, and lumber price of softwood between 1977 and 2011. Linear and threshold cointegration models are used for long-term price analyses, and symmetric and asymmetric error correction models are used for short-term price analyses. The integration in the early stage (i.e., stumpage/delivered timber price pair) is found to be stronger than that in the latter stage (i.e., delivered/lumber price pair). The South shows slightly stronger market cointegration than the West. Asymmetric price transmission is found along the timber supply chain. In the long term, prices are more responsive when the price margin is increased than decreased.     

The role of temperature for seasonal market integration: a case study of poultry in Iran*

Understanding market integration has greatly benefited from analysing and comparing variations in price transmissions. An important source of variation in agricultural markets is seasonal changes in production, consumption and transaction costs. A key factor driving seasonality in agricultural price is temperature, as supply and demand changes are triggered by seasonal temperature differences. In this paper, we study the seasonal variations in vertical price transmission focusing on the asymmetric price adjustment to analyse changes in the market interactions between the stages of the value chain. Our data reveal significant transitory effects of temperature on the price transmission process. Results of a panel threshold model suggest that the farm–wholesale price adjustments to deviations from the market equilibrium are more symmetric at higher temperatures. However, we do not find an effect of temperature on the wholesale–retail price relationship. Our findings can be rationalised with wholesalers making use of their market power to extend their margins in the upstream chain. Wholesaler market power is lower during warm periods, and price adjustment is more symmetric. Concerning the Iranian poultry value chain, our findings imply that temperature-related differences in market interactions should be considered in formulating policy interventions.     

The role of retail market power and state regulations in the heterogeneity of farm‐retail price transmission of private label and branded products

Given the leading role of private label brands in the fluid milk market, it is of special interest to focus on possible differences in farm‐retail price transmission between private label and branded milk as well as the causes of heterogeneity. This article examines the heterogeneous effects of private label and branded products on price transmission in the fluid milk market using a panel threshold asymmetric error correction model. Results indicate that upward retail‐price adjustment is faster than the downward price adjustment for both private label and branded milk. The speed of adjustment of private label products is significantly faster than branded products in three different price regimes. We further investigate the reasons of heterogeneity in farm‐retail price transmission of private label milk. We find that both retailer market power and state pricing regulations contribute to the heterogeneity in asymmetric price transmission. Higher retailer market power causes retail prices of private label milk to rise faster and to fall slower. The existence of a state pricing regulation slows down the adjustment speed of retail prices of private labels back to the long‐run equilibrium, regardless of whether the retail price is low or high.     

Examining long-run relationships between Australian beef prices

Cointegration and impulse response analyses are used to investigate the short-run and long-run dynamics of the Australian beef market. The aim of this study is to determine whether long-run relationships existed between Australian beef prices at the farm, wholesale and retail levels. Based on monthly data from 1971 to 1994, the results show that all three prices considered are cointegrated. Furthermore, the wholesale price is found to be weakly exogenous. The latter result might be an indication of market inefficiency due in part to price levelling often practised in the beef marketing system.     

Local polynomial fitting and spatial price relationships: price transmission in EU pork markets

We study price transmission processes within EU pork marketsafter the implementation of the EU single market in 1993. Wecompare results derived from non-parametric regressions withthose obtained using alternative non-linear threshold models.Both techniques support the hypothesis that prices are transmittedacross spatially separate EU pig markets and provide evidencefor asymmetric price adjustments. They also suggest the existenceof a range of price differentials where equilibrating priceadjustments are less intense. Non-parametric techniques oftensuggest a higher degree of price transmission than that impliedby threshold models.     

Agricultural price transmission across space and commodities during price bubbles

This article investigates agricultural price transmission during price bubbles. The empirical approach concerns the horizontal transmission of cereal prices both across different market places and across different commodities. The trade policy intervention put forward to mitigate the impact of price exuberance is considered. The analysis is performed using Italian and international weekly spot (cash) price data over years 2006–2010, a period of generalized turbulence of agricultural markets. Firstly, the properties of price time series are explored; then, interdependence across prices is specified and estimated by adopting appropriate cointegration techniques. Results suggest that the bubble had only a slight impact on the price spread and the temporary trade‐policy measure, when effective, has limited this impact.     

Asymmetric Price Transmission: A Survey

Asymmetric price transmission has been the subject of considerable attention in agricultural economics. It is not only important because it may point to gaps in economic theory, but also because its presence is often considered for policy purposes to be evidence of market failure. In this paper we survey the literature on asymmetric price transmission. A wide variety of often conflicting theories of, and empirical tests for, asymmetry co‐exist in this literature. We classify the different types and causes of asymmetric price transmission and describe the econometric techniques used to quantify it. We also briefly review the results of empirical applications. Outstanding methodological problems and suggestions for future research are discussed. Our main conclusion is that the existing literature is far from being unified or conclusive, and that it has often been largely method‐driven, with little attention devoted to theoretical underpinnings and the plausible interpretation of results. Hence, much interesting theoretical and empirical work remains to be done.     

国内外玉米价格传导关系影响研究——基于收购政策市场化改革背景

[目的]玉米在国家粮食安全中占有重要地位,是国内外市场联系最为紧密的大宗农产品之一。文章旨在探讨收购政策市场化改革前后,国内外玉米价格传导关系是否发生变化,为政府推进玉米供给侧改革提供理论依据。[方法]该文选取2009—2018年国内外玉米价格周度数据,利用向量误差修正模型和门限向量误差修正模型分别对收购政策市场化改革前后国内外玉米市场间价格传导关系进行实证分析。[结果]长期内,国内外玉米价格存在长期稳定的均衡关系,国际玉米价格对国内玉米价格具有持续稳定的正向传导关系;短期内,收购政策市场化改革前,国内外玉米价格间存在线性调整关系,具体表现为国际玉米价格向国内玉米价格单向传导关系;而收购政策市场化改革后,国内外玉米价格短期非均衡误差调整动态存在门限非对称调整关系,且改革后未来国内玉米价格受到当期国内玉米价格影响较大。[结论]这些结论对推进玉米供给侧改革,维护国内玉米市场的健康有序发展有一定的参考作用。     

A monthly price forecasting Model for cattle and calves

Fluctuations in cattle and calf prices are examined in this study, using monthly data for Canada, for thaperiod 1958 to 1976. Prices for live animals along with wholesale and retail level prices were analyzed. Live cattle prices were. furthermore, studied by type of animals – finished steers, COWS, heifers, feeder steers and calves. The model is formulated on the hypothesis that wholesale prices of beef and veal are first discovered at the wholesale level and live animal and retail prices are then derived from the wholesale prices. Among the live animal prices, price of finished steers was hypothesized to be the price leader, whereas the other live animal prices were determined by it. The wholesale beef price was found to be highly supply flexible (the coefficient being - 1.836), but this was not the case with veal. The flexibility coefficient for live steer (finished) prices with respect to wholesale prices was 0.925. Similarly, the flexibility coefficients for heifer and cow prices with respect to finished steer prices were 0.923 and 0.846. respectively. This suggests that the opportunity cost of females in the breeding herd helps determine the spread between their prices and those of finished steers. Despite the inclusion of economic variables, the study concluded that cyclical fluctuations remained. L'auteur examine dans cette etude les fluctuations des prix bovins et des veaux en utilisant des donnks mensuelles pour la ptriode 1958–1976. Les prix des animaux vivants ainsi que les prix de gros et de detail ont tte analyses dans cette h d e. En outre, l'auteur a entrepris une analyse des prix pour chaque categorie d'animaw – bouvillons A I'engrais. vaches, gtnisses, bouvillons A engraisser et veaux. Le modble explicatif sous-jacent a ttk construit selon I'hypothhe que les prix de gros des veaux et des boeufs s'ktablissaient d'abord sur le march6 de gros. puis les prix des autres animaux vivants et de detail Ctaient ensuite dtduits de ce dernier prix. On a constatt que le prix de gros du boeuf Ctait sensible A toute variation de I'offre (le coefficient ttant & gal A 1,836). Le cas du veau est tout A fait different. Le coefficient de flexibititk pour les prix des bouvillons vivants (A engraisser) par rapport au prix de gros etait tgal A0.925. De la msme facon, les coefficients de flexibilitk du prix des vaches et du prix des gknisses par rapport au prix des bouvillons A l'engrah ttaient respectivement tgaux A 0,923 et 0.846. Ce fait suggbre que le c6ut d'opportunitk des vaches dans le troupeau reproducteur aide A determiner la difference de prix entre les prix des vaches et genisses d'une'part et celui des bouvitlons B l'engrais d'autre part. MalgrC l'inclusion de variables konomiques pertinentes, I'ttude a rtvkle une persistance des fluctuations cycliques.     

The farmer decision process In Purchasing herbicides

Fluctuations in cattle and calf prices are examined in this study, using monthly data for Canada, for thaperiod 1958 to 1976. Prices for live animals along with wholesale and retail level prices were analyzed. Live cattle prices were. furthermore, studied by type of animals – finished steers, COWS, heifers, feeder steers and calves. The model is formulated on the hypothesis that wholesale prices of beef and veal are first discovered at the wholesale level and live animal and retail prices are then derived from the wholesale prices. Among the live animal prices, price of finished steers was hypothesized to be the price leader, whereas the other live animal prices were determined by it. The wholesale beef price was found to be highly supply flexible (the coefficient being - 1.836), but this was not the case with veal. The flexibility coefficient for live steer (finished) prices with respect to wholesale prices was 0.925. Similarly, the flexibility coefficients for heifer and cow prices with respect to finished steer prices were 0.923 and 0.846. respectively. This suggests that the opportunity cost of females in the breeding herd helps determine the spread between their prices and those of finished steers. Despite the inclusion of economic variables, the study concluded that cyclical fluctuations remained. L'auteur examine dans cette etude les fluctuations des prix bovins et des veaux en utilisant des donnks mensuelles pour la ptriode 1958–1976. Les prix des animaux vivants ainsi que les prix de gros et de detail ont tte analyses dans cette h d e. En outre, l'auteur a entrepris une analyse des prix pour chaque categorie d'animaw – bouvillons A I'engrais. vaches, gtnisses, bouvillons A engraisser et veaux. Le modble explicatif sous-jacent a ttk construit selon I'hypothhe que les prix de gros des veaux et des boeufs s'ktablissaient d'abord sur le march6 de gros. puis les prix des autres animaux vivants et de detail Ctaient ensuite dtduits de ce dernier prix. On a constatt que le prix de gros du boeuf Ctait sensible A toute variation de I'offre (le coefficient ttant & gal A 1,836). Le cas du veau est tout A fait different. Le coefficient de flexibititk pour les prix des bouvillons vivants (A engraisser) par rapport au prix de gros etait tgal A0.925. De la msme facon, les coefficients de flexibilitk du prix des vaches et du prix des gknisses par rapport au prix des bouvillons A l'engrah ttaient respectivement tgaux A 0,923 et 0.846. Ce fait suggbre que le c6ut d'opportunitk des vaches dans le troupeau reproducteur aide A determiner la difference de prix entre les prix des vaches et genisses d'une'part et celui des bouvitlons B l'engrais d'autre part. MalgrC l'inclusion de variables konomiques pertinentes, I'ttude a rtvkle une persistance des fluctuations cycliques.     

Derived Demand and Relationships between Prices at Different Levels in the Value Chain: A Note

In this paper we note that when there is only one variable factor in the intermediaries' production technology, prices at different levels in the value chain will move proportionally to each other over time. This is also the only general condition under which the elasticity of price transmission is equal to one, so that retail price signals are perfectly transmitted to primary product producers and vice versa. This allows a test of whether derived demand elasticities contain information about consumer elasticities using only prices. An empirical illustration is provided using data from the Norwegian cod sector.     

Does Market Structure Influence Price Transmission in the Agro‐food Sector? A Meta‐analysis Perspective

There exists a large literature on price transmission in agro‐food sectors. However, a great majority of empirical studies focus on the existence of asymmetry and, by and large, do not investigate the reason for its presence or absence. This is in sharp contrast to the theoretical literature that provides a number of explanations of why we should expect (a)symmetry. In response, this paper investigates the reasons for asymmetric price transmission in the agro‐food chain, using meta‐analysis of existing studies. Our focus is on the organizational and institutional characteristics of the agro‐food supply chain. Our findings suggest that asymmetric price transmission in farm–retail relationships is more likely to occur in sectors/countries with more fragmented farm structure, higher governmental support and more restrictive regulations on price controls in the retail sector. On the other hand, more restrictive regulations on entry barriers in the retail sector and the relative importance of the sector tend to promote symmetric farm–retail price transmission. The latter is also more likely in the presence of a strong processing industry.