OMX Helsinki 25 - Nasdaq
indexes.nasdaqomx.com › Index › OverviewThe OMXH25 Index is a capitalization weighted stock price index. The maximum weight of one company is limited to 10 percent. The composition of the OMXH25 index is revised twice a year. The numbers of shares used to compute the market value are determined on a quarterly basis. On March 4, 1988, the OMX Helsinki 25 Index began with a base of 500.