The case relates to some brokers allegedly getting preferential access through co-location facility at the NSE, early login and dark fibre, which can allow a trader a split- second faster access to data feed of an exchange.
Even a split-second faster access is considered to result in huge gains for a trader.
In a circular, the bourse said OPG Securities will be suspended from trading in the "capital market, futures and options and currency derivatives segments".
The suspension will be effective September 29, 2017, till March 28, 2018, the circular issued yesterday said.
In July, Sebi Chairman Ajay Tyagi had termed the co- location case as "a serious matter".