The Securities and Exchange Commission is preparing new rules to boost oversight of mutual funds, hedge funds and other firms as part of an effort to gain insight into whether the $50 trillion asset-management industry poses risks to the financial system, the Wall Street Journal reported today. The SEC is in the early stages of developing requirements, including that asset managers such as Fidelity Investments and BlackRock Inc. give regulators more data about their mutual-fund portfolio holdings and conduct stress tests on their funds to determine how they would weather economic shocks such as a sudden change in interest rates. The SEC staff is developing the rules with the five-member commission but has yet to complete a formal proposal. Any rule would have to be proposed by the SEC and voted on a second time before being completed, a process that could take months or years.