* Tesla to give customers one-month driver-assist trial; shares up

* McCormick jumps after Q1 profit, sales beat

* Trump Media & Technology surges in debut after SPAC merger

NEW YORK, March 26 (Reuters) -

U.S. stocks were little changed on Tuesday, giving up modest gains late in the session, as investors awaited economic data in a holiday-shortened week to gauge the Federal Reserve's policy path.

Stocks struggled for upward momentum even as Tesla gained after CEO Elon Musk unveiled the electric-vehicle maker's one-month trial of its Full Self-Driving technology to existing and new customers in the United States. The stock is up nearly 5% for the week but remains down nearly 28% for the year.

The focus remains on a key reading of the Personal Consumption Expenditures Price Index (PCE), the Fed's preferred inflation gauge. The data is due on Friday, when U.S. markets will be shut for the Good Friday holiday.

The index is expected to have risen 0.4% in February and 2.5% annually. Core inflation, which excludes volatile food and energy components, is estimated to have advanced 0.3% last month, keeping the annual pace at 2.8%, economists polled by Reuters said.

"The big number is Friday. That's the number everyone's going to pay attention to and whatever happens in the meantime is going to be noise, so I don't anticipate a whole lot happening until we get that data point," said Stephen Massocca, senior vice president at Wedbush Securities in San Francisco.

"The one thing that would be death, death for this market is if somehow something came out that led people to believe that the fed funds rate has not topped out yet. If for some reason people thought the Fed was even giving an inkling to raising rates further, stand out of the way."

On the economic front, orders for long-lasting U.S. manufactured goods increased more than expected in February, while business spending on equipment showed tentative signs of recovery. In a separate report, the Conference Board said its consumer confidence index was little changed at 104.7 in March.

According to preliminary data, the S&P 500 lost 14.09 points, or 0.27%, to end at 5,204.10 points, while the Nasdaq Composite lost 68.77 points, or 0.42%, to 16,320.64. The Dow Jones Industrial Average fell 19.06 points, or 0.05%, to 39,294.58.

The three major U.S. indexes hit record highs last week after the Fed maintained its projection for three interest-rate cuts this year.

Markets have been slowly increasing expectations the central bank will cut rates by at least 25 basis points in June, currently pricing in a 70.4% chance, the CME's FedWatch Tool showed, up from 59.2% last week.

Trump Media & Technology group surged as it kicked off its first day of trading after completing a reverse merger with a blank check firm.

McCormick jumped as the best performer on the S&P 500 after the spice maker beat market expectations for first-quarter sales and profit.

Seagate Technology climbed after Morgan Stanley upgraded the computer hard-drive maker's rating to "overweight" from "equal-weight."

United Parcel Service shares tumbled, however, after announcing its

2026 forecast

.

Trading volumes are expected to be light thoughout the week, thinning out further as the holiday approaches.

(Reporting by Chuck Mikolajczak; Editing by Richard Chang)