The signal from the Fed that markets are watching for today.

“Their goal is just to keep inching toward the taper,” said Gennadiy Goldberg, senior U.S. rates strategist at TD Securities. “Why pre-commit yourself?”

Indeed, there’s a reason for all the tiptoeing. In 2013, when a former Fed chair suggested that a post-financial-crisis bond purchase program would slow, it roiled global markets in what became known as the “taper tantrum.”

Jerome H. Powell, the current Fed chair, has managed to avoid a similar fate so far, but the stakes right now are particularly high. Markets have been rocky this week as investors have fretted about stress in China’s real estate sector and the Fed’s plans. That risk is probably not enough to dissuade central bankers from sticking to the course they have charted, economists said.

“It’s taken some effort to get Fed officials all on the same page, and to get the Fed and the markets on the same page,” Michael Feroli, chief U.S. economist at JPMorgan, said in an email Monday. “I’d be surprised if they want to upend that for something that may be fleeting.”

The Fed is also wrestling with more long-lasting questions about the economic outlook. Inflation has been elevated this year as the economy has begun to reopen from the pandemic and supply has struggled to keep pace with rapid consumer demand, and some measures of consumer inflation expectations are creeping higher. If that continues, rapid price gains could become more permanent.

That would run counter to one of the Fed’s two main goals. The central bank is in charge of keeping inflation low and steady — it aims for 2 percent annual increases in prices on average over time — while fostering maximum employment.

But full employment also remains elusive. Millions of jobs are still missing, even after months of historically rapid employment gains, and officials want to avoid lifting interest rates to cool off the economy before the labor market has fully healed. It’s difficult to know when that might be, because the economy has never had to recover from pandemic-induced lockdowns before.

Tapering bond purchases could give the Fed room to be nimble going forward, allowing it to lift interest rates relatively quickly if it appears that inflation is climbing in a way that is likely to be sustained. Officials have signaled that they would prefer not to lift interest rates before bond buying is brought to a close.

After the Fed releases its statement, Mr. Powell will offer a statement and take questions from reporters at 2:30 p.m.

But outside groups are calling for more, saying those changes are an inadequate response to the deficiencies the episode laid bare.

The trading by the officials “reveals how grossly deficient their ethical standards and the code of conduct are,” Dennis Kelleher, president and chief executive at Better Markets, wrote in a letter to Mr. Powell this week calling for external investigations of what happened. “This requires you to take immediate, concrete and meaningful action, not just P.R. pronouncements of internal investigations and an internal review of the ethics code.”

Mr. Kaplan bought and sold millions of dollars in individual stocks and invested in stock futures, which can allow investors to make bets on whether the market will go up or down, according to his 2020 financial disclosures. Mr. Rosengren traded in financial products tied to real estate, during a year in which he regularly warned the public about risks to that sector. Both said in statements that their investments complied with Fed ethics rules.

A Fed spokesperson said the Fed’s ethics rules are consistent with what most government agencies follow and in some cases more stringent. But given the special role the Fed plays in finance, many have questioned whether it should have stricter requirements.

Fed officials tend to be sophisticated economists and bankers themselves, and their comments can have an outsize impact on financial markets. The central bank has also taken on an increasingly expansive role: Last year, it rescued or aided the short-term corporate debt market, the long-term corporate debt market, the municipal bond market and money market mutual funds.

That raises questions about what sort of securities its officials should be allowed to own. Mr. Powell, for instance, was heavily invested in index funds and municipal debt last year, based on his own disclosures. His municipal bond holdings had not been widely criticized in years past, but they have received negative attention in recent days because the Fed helped that market for the first time last year.

All this poses a conundrum for the Fed, which must weigh what its officials can reasonably invest in, given that its actions influence everything from home prices to the broad stock market.

While there are examples of very high-level officials in government who have put their savings into blind trusts — in which independent money managers buy and sell securities without communicating with the beneficiary about the details of the transactions — those are typically discouraged by the Office of Government Ethics, which calls them “highly restrictive and usually burdensome.” Ethicists tend to instead recommend divesting from individual asset holdings and investing in mutual funds or other broad-based funds.

Many Fed officials, but clearly not all, already do that.

“The system is foolish in the leeway that it gives,” said Mr. Eisen, the former ethics adviser. “The trust system is a recipe for eventual scandal.”

“It is not just the semiconductor issues stretching global supply chains at the moment — it is also the shortage of numerous other products,” Matthias Gründler, the chief executive of Traton, said in a statement. He said he expected the shortages to continue into 2022.

Trucks increasingly come with autonomous driving features and other sophisticated electronics that require semiconductors. Chip makers were not prepared for the increased demand from vehicle manufacturers, and have struggled to maintain production in the face of lockdowns in places like Malaysia, an important semiconductor producer.

A top executive at Daimler’s truck unit said earlier this week that it, too, was suffering. “The situation has become more challenging for us” in the third quarter, Karin Radstrom, the head of Mercedes-Benz brand trucks, said during an online news conference on Tuesday.

“We are currently really fighting for every truck to get it out of the gate,” Ms. Radstrom said, “because the customer demand is very, very good.”

“In the spring of 2020, nobody really knew what to expect,” said Neil Abrams, president of Abrams Consulting Group and a former Hertz executive. “I’ve seen cycles, recessions, peaks and valleys, but nothing quite like this.”

With demand surging and the supply of cars still depressed, rental car companies raised prices. But high prices have a funny way of fixing themselves, at least to some degree:

• Those considering renting will toy around with different modes of transport if rental cars become very expensive.

• Some may decide to optimize their itinerary by using a mix of Uber or public transit to get around.

• Others may turn toward alternatives like Turo or even U-Haul for a car.

Mr. Abrams expects some of the shifts that have taken place in the industry — including higher prices — to be lasting.

“The industry has learned how to do business a different way, and I think the customer is going to get used to this paradigm shift in how cars are rented and how they’re priced,” he said.

Senator Bernie Sanders, the liberal independent from Vermont who chairs the Budget Committee, Ron Wyden of Oregon, the chairman of the Finance Committee and Patty Murray of Washington, a member of Democratic leadership are also slated to head to the White House, as are Senators Jon Tester, from conservative-leaning Montana, and Mark Warner of Virginia.

Senators Joe Manchin III of West Virginia and Kyrsten Sinema of Arizona, centrists who have balked at the price tag of the social safety net plan, also plan to attend, according to their offices.

“We’ve got to do some negotiating moving forward,” Mr. Tester said on Wednesday. “I don’t think that’s a big secret.”

Liberal Democrats in the House remain adamant that they will withhold their votes for the infrastructure bill, which passed the Senate earlier this year, until that chamber approves the $3.5 trillion package. Without their backing, Democrats are almost certain to fall short of the votes they need to win approval of the infrastructure measure in the House, where Ms. Pelosi has committed to bringing it up by Monday.

Representative Ro Khanna, Democrat of California, said Wednesday morning that liberals could not negotiate a final package if more conservative Democrats would not present a counteroffer to the $3.5 trillion measure they have agreed to.

At the very least, he said, Democrats of all stripes need an ironclad, public agreement on a total spending number over 10 years and some core elements that would be in the package, such as an expanded, permanent child care tax credit, a per-child tax credit, and some aggressive climate change provisions, such as a clean energy standard.

Ms. Jayapal is preparing to make the case to Mr. Biden that linking the infrastructure bill to the social policy measure is not a matter of political horse-trading, but a substantive demand.

Liberal lawmakers, she argues, would not have agreed to a traditional infrastructure package funding roads, bridges and tunnels that will promote fossil fuel usage unless they knew a substantial climate change measure would also be enacted, to ensure the vehicles on those new highways would be electric, with a bolstered electricity infrastructure to support them.

For weeks, progressives have insisted that their support for the infrastructure package was contingent on the scope and success of the larger package, which carries most of their ambitions. Democrats plan to push through that bill under a fast-track budget process known as reconciliation that shields it from a filibuster, but because of their slim margins of control in the House and Senate, it can only pass if virtually every member of their party supports it.

With Ms. Sinema and Mr. Manchin warning that they will not back a package so large, and moderates in the House reluctant to vote on a measure that will not become law, Ms. Pelosi has said she will not proceed with the reconciliation bill until it is clear what the Senate can pass.