The Dow Jones Industrial Average finished above 20,000 points for the first time Wednesday, after breaching the milestone at the open, extending a US stock rally following US President Donald Trump's election, which sparked hopes of pro-growth policies.

1. The Dow cracked the psychologically significant threshold of 20,000 within seconds of opening on Wednesday, Jan 25. It closed 155.8 points higher, or 0.8 per cent, at 20,068.51.

2. This marks the second-fastest 1,000-point move in history (42 trading sessions), second only to the 24-session span to reach 11,000 on May 3, 1999.

3. The rally was broad-based and not confined to the Dow, a market index which represents just 30 stocks. The S&P which covers 500 companies and the tech-heavy Nasdaq also closed at new records on Wednesday, climbing 0.8 per cent and 1 per cent respectively.

4. The Dow is now up about 9 per cent since US President Donald Trump's Nov 8 election victory, the S&P 500 has gained nearly 7 per cent, while the Nasdaq Composite Index is up roughly 8 per cent.

5. The market rally is credited to expectations that Trump will unleash a raft of pro-business policies, including tax cuts, more government spending and a rollback of regulations.

6. More specifically, the gains on Wednesday came after Trump signed executive orders on Tuesday to move forward with the construction of controversial infrastructure projects, Keystone XL and the Dakota Access pipelines, which boosted stocks as it supported expectations that Trump was serious about ramping up infrastructure spending - a boon for economic growth. MarketWatch

7. President Trump wasted little time applauding the occasion - by tweet, of course:

8. On the floor of the New York Stock Exchange, traders put on their Dow 20,000 hats, #Dow20K trended on Twitter and the milestone headlined all over the world.

9. But is it just a number?

As a psychological mile-marker Dow 20,000 does matter because the Dow is the "people's index" - the one even non-investors know. But market pundits were quick to warn that there is nothing inherently meaningful about the Dow hitting 20,000 - it's a big round number that's easier to celebrate.

"Just remember that, as far as your long-term investment decisions go, it's a meaningless milestone, an arbitrary "achievement" that, in actuality, means very little - or nothing at all," said The Motley Fool.

10. The Dow milestones have happened much faster in recent years - an achievement that has become a lot more common and a lot less special.

It took the Dow, which was began in 1896, a decade to close over 100, then nearly 66 years to close over 1,000 (which it did in November 1972). The Dow reached 15,000 in May of 2013, while 19,000 was reached about a month ago. The roughly 14 years between Dow 10,000 (March 1999) and 15,000 made that a bigger deal than the three-plus years between 15,000 and 20,000.

11. The market is more than the Dow and the economy is more than the market.

As Bloomberg News editors said in an editorial on Thursday (Jan 26), the stock market is reacting to Trump's plans for the US economy and Dow 20,000 "does not necessarily amount to a vote of confidence in President Donald Trump's ability to deliver economic growth."

Much will depend on the execution - while the markets are also nervous about a protectionist Trump.

Said the Bloomberg editors: "Uncontrolled deficit spending could spook markets and leave the country deeper in debt without providing much long-term benefit. There's still a lot of confusion about what will happen: Measures of economic policy uncertainty are hovering around their highest levels since Britain's vote to leave the European Union."