By Caroline Valetkevitch

NEW YORK (Reuters) -The S&P 500 and Nasdaq registered record closing highs for a second straight day on Tuesday, helped by a gain of more than 7% in Apple shares (NASDAQ:AAPL), while investors also awaited consumer prices data and a policy announcement from the Federal Reserve.

Apple shares jumped 7.3% to a record-high close and gave the S&P 500 and Nasdaq their biggest boosts after the stock declined in the previous session.

At its annual developer event that kicked off on Monday, Apple unveiled new artificial-intelligence features meant to increase the appeal of its devices, including an improved Siri virtual assistant that can answer a wider range of queries and accomplish more complicated tasks than earlier.

The S&P 500 technology index climbed 1.7% and also posted a record closing high.

The Consumer Price Index report will be released before the bell on Wednesday, and the U.S. central bank's policy announcement is due later the same day.

The central bank is likely to leave interest rates unchanged but will release its updated economic projections and "dot plot," which shows where policymakers expect interest rates to stand this year and longer-term.

"Everybody is feeling uneasy, but the data and actions consumers are taking continue to point toward resiliency, and that tends to be overall fairly bullish," said Oliver Pursche, senior vice president and adviser for Wealthspire Advisors in Westport, Connecticut.

The Dow Jones Industrial Average fell 120.62 points, or 0.31%, to 38,747.42, the S&P 500 gained 14.53 points, or 0.27%, to 5,375.32 and the Nasdaq Composite added 151.02

Friday's U.S. monthly jobs report was stronger than expected. Markets have dialed back expectations for the Fed's first rate cut happening in September, now pricing in about a 50% chance, according to the CME's FedWatch tool.

General Motors (NYSE:GM) gained 1.35% after the automaker announced a $6 billion share buyback plan. GM also cut its annual EV production forecast.

After the closing bell, Oracle (NYSE:ORCL) shares rose 8% following the release of quarterly results. The stock ended the regular session down 0.5%.

Declining issues outnumbered advancing ones on the NYSE by a 1.52-to-1 ratio; on Nasdaq, a 1.17-to-1 ratio favored decliners.

The S&P 500 posted 19 new 52-week highs and 4 new lows; the Nasdaq Composite recorded 45 new highs and 127 new lows.

Volume on U.S. exchanges was 10.65 billion shares, compared with the 12.83 billion average for the full session over the last 20 trading days.