The major domestic equity indexes ended the trading day on Thursday in negative territory, as investors worried about potential roadblocks to Republicans’ tax overhaul offsetting their optimism over strong retail sales data.

The holiday shopping season got off to a brisk start, pointing to sustained strength in the economy. The Commerce Department reported Thursday morning that retail sales rose 0.8 percent last month, pointing to sustained strength in the economy. Data for October was revised to show sales gaining 0.5 percent instead of the previously reported 0.2 percent rise.

Average Americans clearly are not holding back on their holiday shopping to see what happens with the tax bill.

And the latest jobless claims numbers showed a surprise drop in the number of people filing for unemployment benefits last week. The weekly jobless claims figure fell to 225,000, not far from the 44-year low of 222,000 reported in October.

It’s true that wages have yet to pick up dramatically. That’s the one weak spot in the labor market. However, you can’t look at wages in isolation. Inflation hasn’t come roaring back either.

Yet, even with skimpy salary increases, a lot of Americans are still making more money in real terms. And they are putting that money back into the economy by spending.

One concern is that higher levels of economic growth about 4 percent could result in some unintended consequences of the upcoming tax cuts.

If tax reform makes the economy grow too fast and eventually brings about higher inflation, the Federal Reserve may have to step up the pace of interest rate hikes.

That could slow down the economy more than many would like. The result could easily be that the Fed raises interest rates four times in 2018, which is more than what Wall Street now expects.

Though congressional Republicans had reached a deal on final tax legislation on Wednesday, Republican Senators Marco Rubio and Mike Lee said on Thursday they would not get behind the bill without changes to child tax credits.

As the fast-moving Republican tax revamp has evolved, it has tilted increasingly toward benefiting businesses and wealthy taxpayers, a trend that aides were saying privately is a growing concern for some lawmakers. Equity investors worry that stocks could tumble if the bill fails.

The S&P, down less than a half a percent from its record closing high hit Tuesday, posted its largest daily percentage drop since Nov. 15.

Healthcare stocks were the largest weight on the S&P 500, falling 1.1 percent. Some portfolio managers said investors were cashing in on recent gains in the sector.

Disney struck a deal to buy Twenty-First Century Fox’s assets for $52.4 billion in stock.

Fox shares rose 6.5 percent to $34.88 and Disney rose 2.8 percent to $110.57, also boosting the consumer discretionary sector, the only major S&P sector in the black on Thursday.

Investors were also digesting the Federal Communications Commission’s vote on Thursday to repeal landmark 2015 rules aimed at ensuring a free and open internet, setting up a court fight over a move that could recast the digital landscape.

Approximately 6.67 billion shares changed hands on the major domestic equity exchanges, a number that was higher than the  6.53 billion share daily average over the past 20 trading sessions.