President Donald Trump claimed on Monday that threats of vigorous new congressional oversight of his administration had caused a market slide.

Trump made the claim on Twitter, where he called out what he termed 'Presidential Harassment' after newly empowered Democrats said they would probe topics from his personal finances, family ethics compliance, and his firing of attorney general Jeff Sessions.

The Dow Jones Industrial Average slid more than 300 points on Monday on news of a distant nature: Apple shares slid nearly 5 per cent on news that a supplier had lowered its outlook, CNBC reported.

An expected drop in lasers used in facial recognition could portend reduced demand for Apple's new iPhone as the holiday season approaches.

President Donald Trump claimed on Monday that threats of vigorous new congressional oversight of his administration had caused a market sell-off, though analysts blamed tech worries for the drop

But Trump concluded the drop was about him and the expectation he and his administration will have to contend with a flood of subpoenas from a Democratic-controlled House.

'The prospect of Presidential Harassment by the Dems is causing the Stock Market big headaches!' Trump wrote, without further explanation.

His complaint came as it emerged that House Democrats have more than six dozen targets for potential subpoenas or investigations and oversight.

Trump tweeted about 'Harassment' as Democrats vowed to investigate his administration

The Dow Jones Industrial Average slid more than 300 points early Monday on news of a distant nature: Apple shares slid nearly 5 per cent on news that a supplier had lowered its outlook, CNBC reported

House Speaker Nancy Pelosi (left) says the Democrats will be strategic in using their subpoena power once they officially take control in January. They have more than 6 dozen potential targets

The incoming House Intelligence Committee chairman is warning new acting attorney general Matt Whitaker any role he plays with the Mueller probe 'will be exposed' – one of several leaders stating more oversight is on the way

President Trump's meeting in Finland with Russian President Vladimir Putin, where the two men met in private, could get additional oversight

Democrats are vowing to scrutinize new acting attorney general Matt Whitaker, who has taken over oversight of the Russia probe after Trump forced out attorney general Jeff Sessions

'The prospect of Presidential Harassment by the Dems is causing the Stock Market big headaches!' Trump wrote as the market took a dive linked to tech companies

The avenues of potential inquiry include President Trump's finances, his family's ethics disclosures, and the president's firing of FBI Director James Comey and Attorney General Jeff Sessions.

Democrats raised the prospect of getting hold of the president's tax returns even before the elections (when the markets were on an upswing) – where a Democratic wave took down close to 40 Republican seats once California results came in.

House Minority Leader Nancy Pelosi is strategizing over which inquiries to prioritize

A list generated by Axios based on public comments and other information lists a whopping 85 potential targets for investigation before Republicans even hand over the gavel.

On the list are payments to porn star Stormy Daniels, who claims she had an affair with Trump. The payment is the basis for a guilty plea in federal court for longtime Trump fixer Michael Cohen, for breaking campaign finance laws at the direction of a candidate (Trump).

The House speaker told Face The Nation Sunday: 'We are not scattershot. We are not doing any investigation for a political purpose, but to seek the truth. So I think a word that you could describe about how Democrats will go forward in this regard is we will be very strategic.'