Adds details from the report in paragraphs 3-4, background in paragraphs 6-7

March 30 (Reuters) - A broker for U.S. Defense Secretary Pete Hegseth attempted to make a big investment in major defense companies in the weeks leading up to the U.S.-Israeli attack on Iran, the Financial Times reported on Monday, citing three people familiar with the matter.

Hegseth's broker at Morgan Stanley MS.N contacted BlackRock BLK.N in February, about making a multimillion-dollar investment in the asset manager's Defense Industrials Active ETF, shortly before the U.S. launched military action against Tehran, the report added.

According to the FT report, the investment discussed by Hegseth’s broker did not ultimately go ahead as the fund, which launched in May last year, was not yet available for Morgan Stanley clients to buy.

The FT report did not say how much discretion the broker had to make investments on Hegseth's behalf, or whether Hegseth knew what the broker was doing.

BlackRock declined to comment on the report, while Morgan Stanley and the Department of Defense did not immediately respond to Reuters' requests for comment.

The report on the investment attempt comes amid a wider scrutiny of trades made in financial and prediction markets ahead of U.S. President Donald Trump's major policy decisions.

Some of these decisions have been preceded by well-timed bets, leading some experts to raise questions about whether information had somehow leaked ahead of time.