(Bloomberg) -- Switzerland’s stock exchange is proposing major changes to its benchmark indexes, including increasing the number of members of the blue-chip SMI by one third and updating the methodology for components.

SIX Swiss Exchange opened a consultation this week with market participants on whether the number of companies listed on SMI should be raised to 30 from 20. 

It’s also proposing that free float market capitalization over 12 months be employed as the sole criteria for its three indexes - the SMI, the 30-member Swiss Leaders Index (SLI), and the SMIM mid-cap index. 

A number of IPOs in recent years, as well as spin-offs such as Accelleron, have increased the overall capitalization and liquidity of the Swiss equity market, according to SIX. It said increased membership would improve the market “in terms of both coverage and diversification,” according to a statement. 

A larger market index means a better representation and better variety for investors, said Ipek Ozkardeskaya, a senior analyst at Swissquote Bank. 

However, she noted the concentration of some large companies — including Nestle SA, Roche Holding AG and Novartis AG — “will still be a handicap for a healthy overall view.” 

“I would find an equal weighted SMI more useful than a larger SMI to be honest,” she said. 

Wolf von Rotberg, an equity strategist at Bank J. Safra Sarasin in Zurich, has a similar view, saying enlargement would “help to reduce the concentration of the index and add some cyclicality,” but the overall impact would be limited. 

“Given that the additional 10 names would only account for around 8% of market cap, these changes are no game changer and the fundamental characteristics of the SMI should largely remain,” he said.

The consultation will run until Nov. 7.

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