¿Cuándo y por qué unifican sus acciones las sociedades que tienen acciones con voto y sin voto?

Según este paper, cuando los beneficios derivados de mantener esa doble estructura del capital (que permite a los insiders controlar la compañía y, a la vez, emitir más capital) no son suficientes para compensar el hecho de perder una posición en el índice bursátil del mercado en el que cotizan porque, para permanecer en el índice (como el Ibex-35 en Madrid) se tenga en cuenta, no la capitalización absoluta de la compañía sino solo la capitalización de las acciones (con voto o sin voto) más líquidas

The paper’s main contribution is to link the literature on dual-class stock unifications with that on index inclusions and deletions. In other words, the paper studies how the trade-off faced by the large, controlling shareholder between the benefits from a dual-class stock unification and the costs from losing control is influenced by the potential loss of index membership.

More specifically, is the large shareholder’s decision as to whether to convert or not influenced by the danger of dropping out of its index? In order to answer this question, we estimate the probability of conversion – conditional on the firm being in danger of dropping out of its index – for various levels of voting rights held by the controlling shareholder.

Our results suggest that the large shareholder is less likely to react to the potential loss of index membership the higher his voting power. This suggests that beyond a certain threshold the private benefits of control foregone by the large shareholder exceed his share of the benefits from unifying the dual-class stock and avoiding the loss of index membership. Similar to the wealth effects accruing to the holders of the non-voting stock that have been documented for the case of regular German stock unifications (see e.g. Dittmann and Ulbricht (2007)), we observe such wealth effects at the announcement of the regulatory change. Finally, while the danger of dropping out of the index is an important reason for conversion, the opportunity to move up an index does not seem to motivate unifications.