UPDATE 1-US SEC, CFTC jointly approve new private fund reporting rules

(Adds Republican reaction and detail from announcements in paragraphs 4-9)

Feb 8 (Reuters) - Two top U.S. markets regulators on Thursday jointly approved new reporting requirements for private funds and investment advisers, saying this would boost the government's ability to spot the build-up of risk in the $20 trillion private investment sector.

The Securities and Exchange Commission and the Commodity Futures Trading Commission also said they had agreed to share the confidential information collected on forms routinely filed by private funds.

The changes will enhance regulators' "understanding of the private funds industry as well as the potential systemic risk posed by the industry and its individual participants," SEC Chair Gary Gensler said in a statement.

Under Gensler, the SEC has tightened oversight of the private investment sector, long criticized for its opacity. His agency last year adopted changes requiring private funds to report fees and performance on a quarterly basis and perform annual audits, among other changes.

Republican members of both agencies said they objected to the decision announced on Thursday.

The changes will apply to SEC-registered funds and those registered with the CFTC as commodity pool operators or trading advisers, the agencies said.

The amendments affect how advisers to large hedge funds will report exposures to investments, counterparties and currencies as well as exposures to countries and industries, the performance of investments by strategy and the liquidity of portfolios, among other things, the SEC said in a statement.

This information can be used by the Financial Stability Oversight Council, an inter-agency body created in the wake of the Global Financial Crisis, to help monitor risk, it said.

In a joint statement, SEC Commissioner Mark Uyeda and CFTC Commissioner Caroline Pham, both Republicans, said the changes were excessive and could jeopardize sensitive confidential data that the CFTC did not need. (Reporting by Douglas Gillison; Editing by Leslie Adler and David Ljunggren)