India will on Thursday sign the tough financial information exchange law enacted by the US, which will also give a boost to New Delhi's own attempts to unearth black money stashed away overseas with information inflow beginning as early as October. The Foreign Account Tax Compliance Act (FATCA) makes it mandatory for all foreign financial institutions to report accounts and financial transaction of US citizens held with them and also accounts of certain foreign entities with substantial US owners. In return, the US will provide India information on investments and financial transactions by its citizens. The US is expected to start sharing information with India from October 1, a senior finance ministry official told ET. FATCA, which came into force on January 1 this year, was enacted by the US in 2010 as part of the Hiring Incentives to Restore Employment (HIRE) Act to combat tax evasion by US nationals holding investments in offshore accounts. India couldn't sign the a