Introduction en bourse

Une introduction en bourse ( ou IPO) est une opération financière conduite par une société et ses différents conseils (banquier d'affaires, commissaire aux comptes, avocat d'affaires, etc.) qui permet la cotation de titres de capital [actions] de cette entreprise sur un marché boursier. Elle est généralement couplée à une levée de fonds (augmentation de capital) et parfois à des cessions d'actions détenues par des actionnaires. Histoire ;Les 10 plus grosses introductions en Bourse de l'histoire des bourses de valeurs : ;Autres introductions *2004 : Google lève 1,9 milliard de dollars. Avantages et inconvénients d'une introduction en bourse ;Avantages Les raisons qui poussent les entreprises à réaliser une introduction en bourse sont les suivantes :

Lever des capitaux propres permettant son développement ; *Acquérir/augmenter sa notoriété/visibilité ;
Offrir une liquidité aux actionnaires actuels ;
Diminuer le coût du capital ;
Rendre les stock-op

Developing structure-oriented models for enzymatic hydrolysis of lignocellulosic biomass

Jessica Charlène Rohrbach

With the unsustainable use of fossil fuels increasing strains on human institutions and ecosystems, the development of a renewable energy alternative is of paramount importance. Second generation biorefineries, based on the production of fuels and chemicals from lignocellulosic biomass, appear as attractive alternative to their non-renewable counterparts. Within the multiplicity of existing valorisation routes, enzymatic hydrolysis of lignocellulosic biomass into its constituent sugars has generated considerable interest, notably in the context of biofuels production. However, major hurdles stemming from the intricate structure of the lignocellulosic feedstocks still impede large-scale deployment of this process. The multiplicity of highly intertwined spatiotemporal factors impacting the enzymatic hydrolysis of lignocellulosic biomass represents a challenge to rationally design efficient hydrolysis process. Here, we propose a theory-based modelling framework relying on pore-diffusion and surface reaction to explore the effects of recognised bottlenecks on the enzymatic hydrolysis of lignocellulosic substrates. The model is based on a set of partial differential equations describing the evolution of the substrate morphology to investigate the interplay between experimental conditions and the physical characteristics of biomass particles as the reaction proceeds. The overall quantity of cellulase present in the hydrolysis mixture is carefully considered to investigate its interplay with the available accessible cellulose surface. Also, non-uniformity in terms of cellulose accessibility and cellulose digestibility are introduced in the model to weight their influence on observed hydrolysis rates. Finally, deactivation mechanisms are considered through unproductive adsorption of cellulases on both cellulose and lignin fractions, with the existence of such phenomena alleged to be critical in the efficiency of the hydrolysis process. Based on predictions of our model, we were able to confirm the critical role of cellulose accessibility, as defined by the combination of particle size, porosity and accessible cellulose surface, in dictating early reaction rates for a range of pretreated beech wood substrates. While high biomass loading should be favoured to improve enzyme penetration in the substrates, high enzyme loadings going beyond the initial number of cellulose adsorption appeared beneficial in notably two cases: (i) to promote internal diffusion in large particles and (ii) counteract undesired enzyme adsorption on lignin. For the latter, a relatively low increase in enzyme loading was sufficient to offset the resulting slowdown. We also showed that the existence of structural heterogeneities, and in particular non-uniform pore volume distribution within the lignocellulosic samples, contribute to the rate slowdown observed at later stage of the hydrolysis, while not explaining it in its entirety. Unproductive adsorption to cellulose, coupled to decrease in the cellulase efficiency at the cellulose surface, appeared as major contributor to the rate slowdown. Overall, we show how the use of a theory-based model can help decouple and evaluate the effects of key factors in the enzymatic hydrolysis of lignocellulosic biomass. As such, our model can help pave the way towards efficient integrated rational design strategies for enzyme process engineering for biomass conversion.

EPFL2021

Signaling and Self-regulation in Venture Capital

Giovanni Liotta

This thesis proposes three studies that provide novel empirical evidence on how different types of VCs' characteristics signal the quality of an entrepreneurial venture and influence investment strategies of funds subject to self-regulation. In the first study we aim at contributing to the ongoing debate on the different effects of reputation and status on organizational outcomes. We explore the signaling value that these two organizational attributes exert on external parties judging the quality of entrepreneurial ventures under uncertainty. Moreover, we examine whether signaling mechanisms are valuable only if the external parties are affected by high information asymmetry with the valued venture. We test our hypotheses using a sample of 1,339 U.S. clean technology ventures that received the first round of Venture Capital (VC) between the years 1990 and 2012. We look at their ability to gather supplemental financial resources for survival and growth by completing an Initial Public Offering (IPO) or an acquisition by an incumbent firm. The findings indicate that VCs' reputation - an economic attribute based on past performance - can signal a venture's quality externally, while VCs' status - a social-standing attribute - does not have signaling value. The results also show that quality signals are more relevant for public investors at IPOs than for managers of acquiring companies. The second study looks at how inter-organizational ties with reputable VCs affect valuations received by entrepreneurial ventures that go public. I propose that the signaling effect of reputable VC ties is lower when there is misalignment of strategic interests between the venture and the VCs. I consider the amount of shares sold by insiders in the initial public offering (IPO) and investors' enforcement of demand registration rights as elements indicating misalignment of interests with the venture. The hypotheses are tested on using a sample of 86 IPOs in the main U.S. stock exchanges completed by entrepreneurial ventures operating in the Clean Technology sector. The results suggest that affiliation with reputable VCs elicits a positive response by public investors. However, public markets react less favorably to ties with reputable VCs when they sell large amount of their shares in the IPO or resort to demand registration rights to force the public offering of their shares. The third study investigates organizations' use of self-regulation as form of symbolic response to normative pressure that does not necessarily entail compliance in practices. I argue that, when self-regulatory initiatives are not supported by an explicit regulatory environment, opportunistic organizations might reduce their efforts to align with the normative ideals through compliant actions and behaviors. The "walking of the talk", which is the implementation of actions that are aligned with the symbolic response, might also be discouraged by alternative means to obtain organizational legitimacy, such as through an organization's status. The hypotheses are tested on a sample of Venture Capital (VC) funds whose limited or general partners voluntarily decided to join the United Nations' Principles of Responsible Investment (UNPRI, 2006) initiative between 2006 and 2014. The results from a difference-in-differences estimation show that VC funds' likelihood to invest in clean technology companies is lower after funds' stakeholders (i.e. general or limited partners) join the UNPRI initiative. I also find that the likelihood to invest in clean technologies after self-regulation is negatively moderated by the VC fund's status.

EPFL2016

Signaling and Self-regulation in Venture Capital

Giovanni Liotta

EPFL2016

Developing structure-oriented models for enzymatic hydrolysis of lignocellulosic biomass

Jessica Charlène Rohrbach

EPFL2021

Field studies of human light exposure during everyday activities - Methodological aspects and initial results

Developing structure-oriented models for enzymatic hydrolysis of lignocellulosic biomass

Signaling and Self-regulation in Venture Capital

Signaling and Self-regulation in Venture Capital

Field studies of human light exposure during everyday activities - Methodological aspects and initial results

Developing structure-oriented models for enzymatic hydrolysis of lignocellulosic biomass