By Caitlin McCabe and Will Horner

The S&P 500 eked out a record close Wednesday after notes from the Federal Reserve's last policy meeting showed that the central bank remains committed to supporting markets and the economy.

The broad benchmark index rose 6.01 points, or 0.1%, to 4079.95, notching its 18th record close of the year. The Dow Jones Industrial Average also rose, gaining 16.02 points, or less than 0.1%, to 33446.26.

The technology-heavy Nasdaq Composite, meanwhile, edged down, falling 9.54 points, or 0.1%, to 13688.84.

The record high for the S&P 500 came after an otherwise anticlimactic day for the U.S. stock market, as major indexes teetered between small gains and losses throughout most of the session. With no clear catalyst to drive markets higher, coupled with below-average trading volumes, stocks largely struggled to find direction.

Still, the S&P 500 and the Dow managed to end the day in the green after the Fed released its minutes from its March meeting in the afternoon. The document showed that Fed officials believe that current guidance for the federal-funds rate and asset purchases was "serving the economy well, " according to the minutes. The central bank has held interest rates near zero and has continued to purchase $120 billion of Treasury bonds and mortgage-backed securities monthly.

Investors and analysts weren't expecting major new pronouncements in the document, especially as Fed officials have continued to publicly reiterate that the central bank is committed to providing support for as long as it takes. Still, some remained on the lookout for hints "around future expectations," said JJ Kinahan, chief market strategist at TD Ameritrade, as well as whether opinions "are starting to splinter within the group."

The minutes showed that central bankers noted "it would likely be some time until substantial further progress toward the Committee's maximum-employment and price-stability goals would be realized."

Most officials also didn't see an outsize risk of inflation becoming an issue, the document showed.

Concerns about inflation have rattled markets this year, as investors have worried that continued economic growth, coupled with government spending, could prompt the Fed to pull back on its support of the economy and markets earlier than expected.

"I think what most people are thinking about is later this year, when we start to get not just one month of really strong employment, but months upon months of strong gains," said Keith Lerner, chief market strategist for Truist Advisory Services.

Signs of economic growth have proved to be a double-edged sword for markets lately. Despite fears that an overheated economy could eventually lead to tightening of monetary policy, investors have simultaneously cheered data that has shown that recovery from the Covid-19 pandemic is under way. On Monday, enthusiasm over the March jobs report, which showed that U.S. employers added a seasonally adjusted 916,000 jobs, propelled the S&P 500 and the Dow to fresh records.

In general, the stock market has kicked off the second quarter on a high note, and the rally has widened. About 94% of companies in the S&P 500 are now trading above their 200-day moving average, according to Dow Jones Market Data as of Wednesday's close.

Signs of that market breadth were evident Wednesday, with stocks ranging from Amazon.com to Carnival to Hess all gaining 1.4% or more. Other winners for the day included L Brands, which jumped $2.25, or 3.6%, to $64.29 after UBS upgraded the stock from neutral to buy. Twitter also jumped $1.99, or 3%, to $68.99.

"We had been expecting the data to improve about this time, and early signals are that the recovery is absolutely on track," said Hugh Gimber, global market strategist at J.P. Morgan Asset Management. "This is the period where the forecast of a strong recovery in growth is starting to look more like the fact of a strong recovery in growth."

U.S. stock investors have been encouraged lately by signs of stabilization in the government-bond market, as bond yields have ticked down after climbing sharply from the start of the year. The yield on the benchmark 10-year U.S. Treasury note fell Wednesday to 1.653%, from 1.656% on Tuesday, notching a third consecutive day of declines.

The recent slip in yields has provided some respite for technology stocks, which had come under pressure from the higher borrowing costs. But many investors continue to bet that it will be the economically sensitive sectors such as banks and energy that stand to benefit most from a reopening.

In commodity markets, Brent crude, the international oil benchmark, gained 0.7% to close at $63.16 a barrel.

Overseas, the pan-continental Stoxx Europe 600 gauge ticked down 0.2%.

In Asia, most major stock indexes were mixed. Japan's Nikkei 225 edged 0.1% higher, while Hong Kong's Hang Seng fell 0.9%. In mainland China, the Shanghai Composite Index dropped 0.1%.

Write to Caitlin McCabe at caitlin.mccabe@wsj.com and Will Horner at William.Horner@wsj.com

(END) Dow Jones Newswires

04-07-21 1724ET