The Dow Jones industrial average — the benchmark U.S. index of blue chip stocks — has closed above the 20,000-point mark for the first time ever.

The most famous stock market average in the U.S. crossed the symbolically significant level when markets opened on Wednesday, the third working day of the new administration. The index ultimately finished the day at 20,068.51, up 155.80 points.

"In and of itself, it is just a number," said Quincy Krosby, market strategist at Prudential Financial told AP. "But what it does is it lifts market expectations, in essence, to continue moving higher."

New U.S. President Donald Trump has rolled out orders overturning Obama policies every day this week, including moves to pull out of the Trans Pacific Partnership (TPP), and a move to ease regulatory burdens on businesses.

"Trump's been on the job for five days and he's a man of action," said Brian Battle, director of trading at Performance Trust Capital Partners in Chicago told Reuters. "That should get everyone confident he'll get those three other things done ... which is taxes, trade and regulation."

Calling it a "huge day for the markets" chief strategist Colin Cieszynski at CMC Markets told CBC News in an interview the 20,000-point milestone for the Dow was more than just a "big psychological barrier" but a sign of widespread economic optimism.

The broader S&P 500 and the tech-heavy Nasdaq Composite index also closed at new all-time highs for a second consecutive day. "We're getting some really great breadth as the broader indices are following the Dow higher," Cieszynski said.

Part of that is a so-called "Trump bump" as investors digest the reality of a new pro-business president, he said.

The TSX also eclipsed its own all-time closing record of 15,657 that the benchmark Canadian stock index set back in 2014, before falling back to close at 15,643.84 for a gain of 33.15 points.The all-time intraday high still sits at 15,685, set on Sept. 3 that year.