Intraday Comparisons against Trump tariff pause day


Setting the scene

I found it interesting that when Trump made his 10% tariff decision on the 9th (04/09/25), he had posted on his social media site that it was a "GREAT TIME TO BUY!!!".

"THIS IS A GREAT TIME TO BUY!!! DJT," he wrote on his social media platform Truth Social at 9:37 a.m.
It may be just me but my first thought was insider trading. Not the usual insider trading. This is where an individual in a corporation passes insider information that will affect stock price to an individual outside the corporation that results in windfall gains. The inovation here would be that it's government policy and not corporation information that is involved. Also, it is not being passed to an individual but posted to social media. Not as direct information but as hint, hint, wink, wink, three exclamation marks. Rather than insider trading this is speculated to be market manipulation in this article.

I heard it mentioned that someone quickly pointed out that this was was just Trump doing his job, to encourage the markets. My first thought here was of the Trump v. United States decision. This was that "presidential immunity from criminal prosecution presumptively extends to all of a president's 'official acts' - with absolute immunity". It seemed like someone wanted to remind everyone, before they thought any different, that Trump already held a get out of jail free card from the highest court in the land.

Hon. Marjorie Taylor Greene

There was subsequent news that Marjorie Taylor Greene had made a number of stock purchases on the day before and the day of the tariff pause announcement. The suggestion again being that possible insider trading or Front running was involved. This is considered in Marjorie Taylor Greene bought thousands of dollars in stock right before Trump's tariff pause sent markets soaring.
Her Response...
"All of my investments are reported with full transparency," Greene added.
There was in fact disclosure made. This details exactly what she bought. This gives me a block of stocks that I can compare and contrast against the stocks mentioned in the first article above. This trading will be discussed more later.

Intraday Comparisons

Regarding the above market manipulation article it mentions that at end of day the possibly Trump related stocks TSLA - Tesla, and DJT - Trump Media & Technology Group, did better than other stocks. What seemed to me would somewhat confirm if the Trump post had the effect of mass insider trading would be if there were unusual volume or price changes between the time of the post, 9:37AM (or right after market open) as shown above, and the time of the tariff 10% pause announcement, I saw somewhere was around 1PM. For each of these periods I look at the actual day, the previous day, the days in April before the day, and the days since the day. All divided the same way. The hours of the day can matter. From Best Times of the Day, Week, and Month to Trade Stocks

The closest thing to a hard-and-fast rule is that the first hour and last hour of a trading day are the busiest, offering the most prospects, while the middle of the day tends to be the calmest and most stable period of most trading days.
Although, I'm not sure it is relevant here, I try to control for what I can and not compare apples to oranges.

I wrote some java for this using Stooq intraday Market Data.