A Grey-Box Approach to Automated Mechanism Design

Auctions play an important role in electronic commerce, and have been used to solve problems in distributed computing. Automated approaches to designing effective auction mechanisms are helpful in reducing the burden of traditional game theoretic, analytic approaches and in searching through the large space of possible auction mechanisms. This paper presents an approach to automated mechanism design (AMD) in the domain of double auctions. We describe a novel parametrized space of double auctions, and then introduce an evolutionary search method that searches this space of parameters. The approach evaluates auction mechanisms using the framework of the TAC Market Design Game and relates the performance of the markets in that game to their constituent parts using reinforcement learning. Experiments show that the strongest mechanisms we found using this approach not only win the Market Design Game against known, strong opponents, but also exhibit desirable economic properties when they run in isolation.Comment: 18 pages, 2 figures, 2 tables, and 1 algorithm. Extended abstract to appear in the proceedings of AAMAS'201

Agent-orientated auction mechanism and strategy design

Agent-based technology is playing an increasingly important role in today’s economy. Usually a multi-agent system is needed to model an economic system such as a market system, in which heterogeneous trading agents interact with each other autonomously. Two questions often need to be answered regarding such systems: 1) How to design an interacting mechanism that facilitates efficient resource allocation among usually self-interested trading agents? 2) How to design an effective strategy in some specific market mechanisms for an agent to maximise its economic returns? For automated market systems, auction is the most popular mechanism to solve resource allocation problems among their participants. However, auction comes in hundreds of different formats, in which some are better than others in terms of not only the allocative efficiency but also other properties e.g., whether it generates high revenue for the auctioneer, whether it induces stable behaviour of the bidders. In addition, different strategies result in very different performance under the same auction rules. With this background, we are inevitably intrigued to investigate auction mechanism and strategy designs for agent-based economics. The international Trading Agent Competition (TAC) Ad Auction (AA) competition provides a very useful platform to develop and test agent strategies in Generalised Second Price auction (GSP). AstonTAC, the runner-up of TAC AA 2009, is a successful advertiser agent designed for GSP-based keyword auction. In particular, AstonTAC generates adaptive bid prices according to the Market-based Value Per Click and selects a set of keyword queries with highest expected profit to bid on to maximise its expected profit under the limit of conversion capacity. Through evaluation experiments, we show that AstonTAC performs well and stably not only in the competition but also across a broad range of environments. The TAC CAT tournament provides an environment for investigating the optimal design of mechanisms for double auction markets. AstonCAT-Plus is the post-tournament version of the specialist developed for CAT 2010. In our experiments, AstonCAT-Plus not only outperforms most specialist agents designed by other institutions but also achieves high allocative efficiencies, transaction success rates and average trader profits. Moreover, we reveal some insights of the CAT: 1) successful markets should maintain a stable and high market share of intra-marginal traders; 2) a specialist’s performance is dependent on the distribution of trading strategies. However, typical double auction models assume trading agents have a fixed trading direction of either buy or sell. With this limitation they cannot directly reflect the fact that traders in financial markets (the most popular application of double auction) decide their trading directions dynamically. To address this issue, we introduce the Bi-directional Double Auction (BDA) market which is populated by two-way traders. Experiments are conducted under both dynamic and static settings of the continuous BDA market. We find that the allocative efficiency of a continuous BDA market mainly comes from rational selection of trading directions. Furthermore, we introduce a high-performance Kernel trading strategy in the BDA market which uses kernel probability density estimator built on historical transaction data to decide optimal order prices. Kernel trading strategy outperforms some popular intelligent double auction trading strategies including ZIP, GD and RE in the continuous BDA market by making the highest profit in static games and obtaining the best wealth in dynamic games

Cover Pricing and the Overreach of ‘Object’ Liability under Article 101 TFEU

This article uses the example of cover pricing to show a possible overreach of liability under Article 101 TFEU, in relation to arrangements deemed to have the ‘object’ of restricting competition. Cover pricing is where a bidder seeks a non-winning bid from a competitor so that he can participate in a tender process without securing the contract. The wide meaning of ‘concerted practice’ means that a potential breach of Article 101 may arise even where the party receiving the request refuses to provide a cover bid. It is important that a restriction by object (which leads to the finding of an infringement regardless of whether the practice was implemented or had any harmful effect) applies only to the most serious arrangements between undertakings. It is shown that cover pricing very rarely has any anti-competitive effect and indeed the alternative (lawful) behaviour, of openly announcing a non-intention to win the contract, is more likely to reduce competition. It is nevertheless treated as an object restriction, mainly because it involves direct communication between competitors of pricing intentions. Article 101 may therefore be unable to distinguish some arrangements with ambivalent effects from the most serious cartel practices. It is argued that a greater effects analysis is needed (either in applying the law or calculating penalties), to ensure fairness and proportionality

A Game-Theoretic Analysis of Market Selection Strategies for Competing Double Auction Marketplaces

In this paper, we propose a novel general framework for analysing competing double auction markets that vie for traders, who then need to choose which market to go to. Based on this framework, we analyse the competition between two markets in detail. Specifically, we game-theoretically analyse the equilibrium behaviour of traders' market selection strategies and adopt evolutionary game theory to investigate how traders dynamically change their strategies, and thus, which equilibrium, if any, can be reached. In so doing, we show that it is unlikely for these competing markets to coexist. Eventually, all traders will always converge to locating themselves at one of the markets. Somewhat surprisingly, we find that sometimes all traders converge to the market that charges higher fees. Thus we further analyse this phenomenon, and specifically determine the factors that affect such migration

Development of an Autonomous Double Auction Market for its Effective Operation in Competitive Environments

The objective of this thesis is the development of an autonomous Double Auction (DA) market capable of operating efficiently in an isolated as well as in competitive environments. A well known example of such an institution is the stock market. Besides their multi-annual study and operation, DAs continue constituting a theoretical paradox. They succeed to exhibit an increased efficiency with the implementation of very simple rules, even if there still has not been achieved a satisfactory theoretical model from the field of Mechanism Design. In order to overcome this shortcoming, researchers have turned their attention to experimental techniques for the study and implementation of new, innovative rules, a field known as Automated Mechanism Design. However, all studies up to now deal with markets that operate free of charge in an isolated environment, something which does not correspond well in today’s global economy, where each country’s stock markets compete with each other as well as with the remainder stock exchanges worldwide in order to achieve high profits and market-share. TAC Market Design (or CAT) is an attempt to study this kind of institutions and made its appearance in 2007. In CAT, entrants represent stock markets that compete with each other while being evaluated in a number of realistic criteria. This thesis presents the game of CAT and all the strategies that were implemented by our agent, Mertacor, with which we participated these two years that the competition is being conducted and which was placed 8th and 5th respectively

Congestion Control and Vehicle Ownership Restriction: The Choice of an Optimal Quota Policy

Singapore introduced a vehicle quota system (VQS) in 1990 as part of its overall policy to control urban congestion. While the VQS has reduced the annual growth rate of the vehicle population to about 3%, it has created uncertainty in the cost of vehicle ownership due to the fluctuations in license prices. The paper discusses three issues relating to the optimal design of a VQS: license transferability, subcategorization and the choice of an auction format. Our analysis shows that license transferability is not unambiguously desirable, sub-categorization is highly regressive, and an open auction format results in less aggressive bidding and lower license prices.congestion control, vehicle ownership, optimal quota, transport policy

Setting Fees in Competing Double Auction Marketplaces: An Equilibrium Analysis

In this paper, we analyse competing double auction marketplaces that vie for traders and need to set appropriate fees to make a profit. Specifically, we show how competing marketplaces should set their fees by analysing the equilibrium behaviour of two competing marketplaces. In doing so, we focus on two different types of market fees: registration fees charged to traders when they enter the marketplace, and profit fees charged to traders when they make transactions. In more detail, given the market fees, we first derive equations to calculate the marketplaces' expected profits. Then we analyse the equilibrium charging behaviour of marketplaces in two different cases: where competing marketplaces can only charge the same type of fees and where competing marketplaces can charge different types of fees. This analysis provides insights which can be used to guide the charging behaviour of competing marketplaces. We also analyse whether two marketplaces can co-exist in equilibrium. We find that, when both marketplaces are limited to charging the same type of fees, traders will eventually converge to one marketplace. However, when different types of fees are allowed, traders may converge to different marketplaces (i.e. multiple marketplaces can co-exist)

Independent Sector Regulators and their Relationship with Competition Authorities

Independent sector regulators and competition authorities share many objectives and common interests, particularly because they both can play key roles in promoting effective and beneficial competition. In this note, the criteria and rationale for the independence of sector regulators and competition authorities are explained, along with a suggestion that independence may sometimes be especially critical for institutions with broad economic oversight and quasi-judicial responsibilities or, alternately, for institutions most subject to influence of special interests. The note suggests that sector regulators may benefit, in times of high technological change and uncertainty, from principle-based laws that allow regulators the flexibility to adjust their precise rules in light of evolving circumstances. Moreover, the note suggests that in some respects, the sectors subject to independent regulation may usefully include other sectors beyond those most traditionally associated with independent regulation. Ultimately, ensuring consistency and convergence between sector regulator and competition authority objectives and actions is important; ironically, independence can make ensuring such consistency through direct co-operation a challenge. Based on international experience, multiple mechanisms exist for achieving or encouraging such consistency; some combination of these merits consideration by designers of competition policy regimes