U.S. Treasury bonds were little changed Wednesday following the previous day’s selloff and ahead of the Federal Reserve’s decision over whether the time is ripe to raise interest rates for the first time in nearly a decade.

Many investors see a low probability that the central bank would pull the trigger on Thursday amid sluggish global economic growth, contained inflation and a recent stock-market swoon. Expectations for the Fed to stand pat boosted prices of stocks and commodities Wednesday. The dollar, which has benefited from the prospect of higher interest rates in the U.S., pulled back.

“It is a tossup, but my bias is that [the Fed] won’t move,” said David Ader, head of government bond strategy at CRT Capital Group LLC. “Inflation is still tame and the financial markets remain unsettled. Why not wait for a few more weeks?”

In recent trading, the yield on the benchmark 10-year Treasury note was 2.280%, compared with 2.281% Tuesday which was the highest closing level in nearly two months, according to Tradeweb. Yields fall as bond prices rise.

The yield on the two-year note was 0.787%, compared with 0.798% on Tuesday which was the highest closing level since April 2011. Short-term bond yields are highly sensitive to changes in the Fed’s interest-rate policy outlook.

“The market has stabilized…but remains very nervous before Thursday’s rate decision,” said Anthony Cronin, a Treasury bond trader at Société Générale SA.

The Fed is scheduled to release an interest-rate statement Thursday afternoon along with updated projections on U.S. interest rates, growth and inflation, followed by a news conference by Fed Chairwoman Janet Yellen.

Fed-funds futures, used by investors and traders to place bets on central bank policy, showed Wednesday that bettors see a 21% likelihood of a rate increase on Thursday, according to data from CME Group. The odds were 23% Tuesday and 45% a month ago.

The uncertainty on the Fed has whipsawed the bond market this week. A resilient retail sales report Tuesday bolstered the case for a rate increase, which sparked a broad selloff. But Wednesday, the latest inflation indicator stayed below the Fed’s 2% target, supporting those calling for the Fed to wait longer to act.

The Fed’s ultraloose monetary policy has pushed up Treasury bond prices to historically elevated levels and bond investors are concerned that the value of bonds may fall once the Fed shifts gear into a tightening mode. Higher interest rates typically make newly minted bonds more attractive and shrink the value of outstanding bonds.

On the other hand, concerns over anemic global growth, in particular the slowdown in China’s economy, have supported demand for long-term Treasury debt. The dueling forces have kept a lid on long-term Treasury bond yields, making investors more cautious in wagering bets that bond prices would sell off.

Fence-sitting dominated the latest weekly Treasury client survey from J.P. Morgan Chase & Co. on Tuesday, a widely followed gauge of investor sentiment. A total 61% of investors polled say they were neutral on bond prices for the week ending Monday, compared with 63% a week ago.

Those who expect bond prices to rise accounted for 17%, unchanged from a week ago, while 22% expected bond prices to fall, compared with 20% a week ago.

Russ Certo, managing director of rates trading at broker dealer Brean Capital LLC in New York, said there hasn’t been a “unified” strategy from his clients over the past week to prepare for the Fed given the lack of consensus of the Fed’s move.

“Investors got burned before in the bond market,” which has made many cautious in betting against long-term bonds, said Mr. Certo.

Traders say short-term bond yields would rise if the Fed raises interest rates Thursday. Should the Fed hold off, short-term yields may fall in response. But some analysts say the reprieve may not last long, as the Fed is still on track to raise rates regardless of the timing.

The Fed’s rate policy has a more subdued impact on long-term bonds as their yields are more influenced by the global growth and inflation. The 10-year Treasury yield, a benchmark to set long-term interest rates for U.S. consumers and businesses, has fallen after hitting this year’s peak of 2.5% in June.

Some traders say long-term Treasury bonds may weaken if the Fed holds off on Thursday. The rationale is that the longer the Fed holds the policy rate near zero, the bigger the risk that the Fed may fall behind the battle in controlling inflation, which chips away bonds’ fixed value over time.