India is ramping up scrutiny of Wall Street traders with the nation's securities regulator turning more aggressive in targeting even prominent foreign players like JPMorgan Chase & Co. in its $5 trillion stock market. That push has been on display in recent days as the Securities and Exchange Board of India accused a Mauritius-based JPMorgan unit of executing manipulative stock trades. Last year, in one of its most dramatic actions on a foreign firm, SEBI accused Jane Street of market manipulation, an allegation that the US financial giant has denied.