OTTAWA – Faced with new questions over the sell-off of Morneau Shepell shares -- this time by his father -- Bill Morneau is denying that he spoke with him about a coming tax policy change ahead of time.

CTV News has confirmed that the finance minister's father sold 200,000 shares in Morneau Shepell, the company he founded, days before his son brought forward a tax change that raised taxes on the wealthiest one per cent and lowered them for the middle class.

According to insider trading reports, William F. Morneau Sr. sold 100,000 Morneau Shepell Inc. shares at $15.20 per share on Nov. 23, 2015, and another 100,000 shares at $15 a share on Dec. 3.

The finance minister announced the government would be changing the income tax act, through Bill C-2, An Act to amend the Income Tax Act, on Dec. 7, 2015. That day, the stock market dropped.

The opposition is alleging the timing is no coincidence, nor is it that someone else sold 680,000 Morneau Shepell shares ahead of the major tax change.

Morneau has called these accusations baseless and has threatened to sue the opposition for making them, if they are repeated outside of the House of Commons where MPs don’t have parliamentary privilege.

"There are no secrets here. As has been reported in the press, when I came into office, I sold some shares. As has been reported, when I came into office, I made a $5 million donation to charity. As we know, we campaigned to 36 million Canadians that we would raise taxes on the 1 per cent, which we did. As everyone knows, except for perhaps the opposition, no one knows what the stock market will do in advance," Morneau said in question period on Wednesday.

On Thursday, he denied discussing his plans to sell his shares with his father, as well as denying discussing with his dad the timing of moving forward on tax changes.

"I did not at any point in time, nor would I at any point in time, discuss any confidential information with my father or with anyone else… His decision on his financial affairs, are his and his alone," Morneau told reporters in the House of Commons foyer on Thursday afternoon following question period.

He said it's likely his father would have known that the Liberals, upon forming government, would move on the tax reform, as it was a campaign promise. The new tax policy did not come into force until Jan. 1, 2016.

Wednesday, Conservative Leader Andrew Scheer called for Morneau’s resignation from his finance post, saying his caucus had lost confidence in him over the unanswered questions about his stocks, and the ongoing ethics investigation into Morneau over another piece of legislation he tabled.

"It is clear that under a cloud of investigation and serious questions about his dealings going unanswered, he should not continue in his role," Scheer said.

Morneau said Thursday he had "no idea how slanderous the opposition would be."

CTV News has reached out to William F. Morneau Sr. for comment.

With files from CTV News' Mackenzie Gray and Glen McGregor