Another successful session for US stocks has sent the Standard & Poor's 500 index higher for an eighth straight day.
That is the index's longest winning streak since July 2013, which was months before Twitter shares started trading publicly.
It is the latest step higher for a market that has methodically climbed to record after record for much of this year as both the economy and corporate profits have improved.
The S&P 500 rose 14.33 points, or 0.6%, to 2,552.07. The Dow Jones industrial average gained 113.75, or 0.5%, to 22,775.39 and the Nasdaq composite rose 50.73, or 0.8%, to 6,585.36. All three indexes added to their records set a day earlier, again.
But all those moves higher have made some professional investors a bit nervous, because even the healthiest markets tend to have some sharp sell-offs from time to time. The last time the S&P 500 had a pullback of just 5% was more than a year ago.
"What's really troubling most people more than anything is that we just go straight up," said JJ Kinahan, chief strategist at TD Ameritrade. "There hasn't been a pullback. That's what most on Wall Street are trying to come to grips with."
Encouraging reports on the economy have been helping stocks, and on Thursday they included a stronger-than-expected rebound in US factory orders during August and a drop in the number of workers applying for unemployment benefits last week.
Friday's report from the Labor Department on monthly job growth will likely show momentum in the opposite direction, with most economists forecasting a drop-off in hiring. But that is mostly because of damage caused by recent hurricanes, which hopefully will be only temporary.
With the economy and corporate earnings seemingly solid, Mr Kinahan said if there is a trigger for a downturn in stocks, it would likely be either a new flash in political tensions with North Korea or somewhere else in the world, or a stumble in Washington's progress to reform the tax system.
Netflix jumped to the biggest gain in the S&P 500 Thursday after it raised the price on its most popular US video streaming plan by 10%.
The yield on the 10-year Treasury note climbed to 2.34% from 2.32% late on Wednesday. Higher interest rates tend to help financial stocks on the expectation that banks will make bigger profits from lending, and financials in the S&P 500 rose 1%.