By Anna Hirtenstein

U.S. stock futures wobbled, suggesting major indexes will pause after notching records at the end of last week.

Futures tied to the S&P 500 fell 0.1%. Contracts linked to the Dow Jones Industrial Average slipped 0.2% and Nasdaq-100 futures wavered between gains and losses.

Investors started the week on a cautious note amid concerns that the rollout of Covid-19 vaccines was facing hiccups. A string of blue-chip companies are scheduled to report earnings this week, and will offer a view on businesses' expectations for the pace of economic revival. Money managers are looking to gauge whether stocks' high valuations are justified after the Dow and S&P 500 hit closing records last week.

"After a big move, you get a pause of breath and a bit of a reassessment, " said Caroline Simmons, U.K. chief investment officer at UBS Asset Management. "People are reassessing, waiting for newsflow that might indicate that growth and inflation remain on track."

U.S. health authorities decided to recommend pausing the use of the Johnson & Johnson vaccine due to concerns about improper treatment of blood clots, The Wall Street Journal reported over the weekend. Health officials are now looking at limiting the J&J vaccine to older people, among other options, and could make public a decision as early as this week.

On the earnings front, Coca-Cola is scheduled to post its numbers at around 6:55 a.m. ET. International Business Machines is expected to report after the close.

"I expect the earnings picture is going to remain very buoyant across the picture and for the momentum to stay very positive," said Fahad Kamal, chief investment officer of Kleinwort Hambros. "As long as earnings meet what are very heightened expectations, the rally can keep going."

In bond markets, Treasury yields declined sharply toward the end of last week and continued to edge down Monday. The 10-year yield ticked down to 1.562%, from 1.571% on Friday. Yields fall when bond prices rise.

"The slowdown in vaccine rollouts and increased lockdowns could be having a marginal influence on bond yields," said Ms. Simmons. "People are seeking safe havens."

In premarket trading, Peloton fell 5.3% after a federal safety agency said over the weekend that people with young children or pets shouldn't use the connected-fitness company's treadmills. Tesla declined 1.4%, after two men died in a Tesla vehicle that crashed into a tree Saturday.

In currency markets, the Russian ruble weakened 0.4% against the dollar. U.S. officials warned there would be consequences if opposition politician Alexei Navalny dies in prison. Calls for mass protests in cities across Russia also mounted. The ruble has lost nearly 3% of its value this year.

Bitcoin rose nearly 1.5% to about $57,100, regaining some ground after plunging almost 12% over the weekend, according to data from CoinDesk. Turkey's central bank said Friday it would ban the use of cryptocurrencies as a form of payment.

"The [cryptocurrency market] is really on edge right now," said Joel Kruger, a currency strategist at LMAX. "There were concerns over the weekend after Turkey came out with the news of major regulatory restrictions coming into force."

Some traders were speculating that the U.S. Treasury could make a similar decision, he said.

Overseas, the pan-continental Stoxx Europe 600 edged up 0.2%, on track to notch a record closing high for the third consecutive trading session.

In Asia, most major benchmarks ticked up by the end of the day. The Shanghai Composite Index climbed 1.5% for its best day in over three weeks. Hong Kong's Hang Seng added 0.5%. However, India's benchmark stock index fell 1.8% as Covid-19 cases continued to climb.

Write to Anna Hirtenstein at anna.hirtenstein@wsj.com

(END) Dow Jones Newswires

April 19, 2021 06:57 ET (10:57 GMT)

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