The Securities and Exchange Board of India is intensifying its investigation into a large-scale pump-and-dump operation involving shell companies, in what is emerging as one of its biggest enforcement crackdowns, people in the know told NDTV Profit.More than 200 privately listed companies are likely under the regulator’s scanner, with the focus on entities suspected of artificially inflating stock prices and offloading them to unsuspecting investors.SEBI is examining data extracted from over 150 mobile devices and more than 100 computers, the people cited above said. The last tranche of searches, carried out recently, spanned across three days and covered more than 80 premises.As first reported by NDTV Profit on June 30, SEBI is probing a suspected network of shell companies. Many of them, operating out of Ahmedabad, allegedly used to manipulate stock prices through coordinated social media campaigns and false narratives.The probe is data-heavy and involves detailed forensic analysis of digital devices seized during multiple raids, the people said.SEBI Probing Spright Agro For Suspicious Share Issue Activities | Profit Exclusive. Read more on Markets by NDTV Profit.