US benchmark equity indexes ended lower Tuesday as investors weighed a slump in allocation to US equities in a Bank of America (BAC) survey and the Federal Reserve kicked-off its policy meeting.

* A closely monitored Bank of America survey of global fund managers, with 171 participants polled in March, showed a 40-point drop in allocations to US equities month over month. The monthly slump is reportedly a record decline that strategists at the investment bank called a "bull crash."

* The two-day Federal Open Market Committee meeting will most likely leave interest rates unchanged, as per the CME FedWatch tool, after accounting for the state of the labor market and inflationary pressures in the economy.

* The markets know from the January FOMC minutes that the Fed is considering slowing or pausing the pace of quantitative tightening given "the potential for significant swings in reserves over coming months related to debt ceiling dynamics," according to a note from the Wells Fargo Investment Institute.

* April West Texas Intermediate crude oil closed down $0.69 to settle at $66.89 per barrel, while May Brent crude, the global benchmark, was last seen down $0.53 to $70.54 as talks between US President Donald Trump and Russian counterpart Vladimir Putin for a Ukraine ceasefire offset rising tensions in the Middle East after Israel broke its Gaza ceasefire with the Hamas militant group by launching strikes.

* Appili Therapeutics, which is in the process of being acquired by Aditxt (ADTX), submitted applications for four new federal funding prospects for a combined $117.5 million to support efforts to advance urgent infectious disease treatments. Aditxt's stock surged 71%.

* Alphabet's (GOOG) Google agreed to acquire cybersecurity startup Wiz in an all-cash deal worth $32 billion as the technology giant looks to bolster its cloud security operations. Shares were down over 2%.