Eight years ago, Congress passed the Stop Trading on Congressional Knowledge, or STOCK, Act. The law extended insider trading restrictions to members of Congress.

Yet even if Republican Sens. Richard Burr and Kelly Loeffler did trade on knowledge about the coronavirus they obtained through their jobs, it may have been perfectly legal.

That said, the transactions, and the lack of immediate disclosure, are ethically troubling at least.

Loeffler is the appointed senator from Georgia, filling out the term of Johnny Isakson, who resigned at the new year. Loeffler's husband is the chairman of the New York Stock Exchange. Loeffler and her husband sold millions of dollars in stocks ahead of the market’s late-February collapse, as first reported by the Daily Beast’s Lachlan Markay (author of Sinking in the Swamp), William Bredderman, and Sam Brody.

Burr is the chairman of the Senate Intelligence Committee. He and his wife sold somewhere between $628,000 and $1.7 million in stock ahead of the coronavirus collapse, as first reported by Karl Evers-Hillston at the Center for Responsive Politics.

Both lawmakers deny any wrongdoing. Loeffler has suggested that she and her husband don’t control their investments but instead let a manager handle it for them. Burr has defended his sales, saying, "I relied solely on public news reports to guide my decision regarding the sale of stocks on February 13. Specifically, I closely followed CNBC's daily health and science reporting out of its Asia bureaus at the time.”

Phrases such as “insider trading” and “conflict of interest” have flown around the media in the wake of these revelations, with some critics pointing to the STOCK Act. From what we currently know, however, it seems very unlikely Loeffler traded on insider information, and it’s impossible to say whether Burr did. And we may never know.

To be guilty of insider trading, one needs to be an insider. Specifically, one would have to be trading on “material, non-public information.” Even if Loeffler were ordering her own stock sales, which she says she was not doing, it seems unlikely she received any "insider" information from her role as a senator.

The Daily Beast article refers to a Jan. 27 all-senator briefing by “senior administration officials” hosted by two Senate committees — health and foreign relations. But the odds are slim, judging by conversations with multiple, senior Senate staffers, that senators in this briefing were given any nonpublic information.

Maybe senators who attended did emerge better informed than the vast majority of the public — and thus more worried about a pandemic wreaking havoc on the U.S. economy. But being very well informed thanks to your job does not amount to having “non-public information.”

On the other hand, if administration officials told the senators that the White House was about to take some serious action, or if they passed along nonpublic information from intelligence officials, then senators would be prohibited by law from trading on it. But again, that seems unlikely in Loeffler's case.

Burr’s trades are more problematic. The Senate Intelligence Committee, which he chairs, has been receiving daily updates from intelligence agencies, according to Reuters. I called Burr’s office and asked if Burr received any nonpublic information on the coronavirus in those briefings. Burr’s spokeswoman declined to comment, partly because Intelligence Committee briefings are classified and partly because Burr has now asked the Senate Ethics Committee to look into the matter.

There’s no guarantee the Ethics Committee could ever adequately investigate whether Burr committed insider trading because the committee may not have adequate clearance to learn exactly what information U.S. officials passed on to Burr.

Senators are further protected by the fact that conflict-of-interest rules for senators are nebulous. While executive branch officials (notably, excepting the president) have strict rules about what stocks they can and cannot hold and what transactions they can and cannot make, senators are mostly allowed to self-police.

Senators must file reports after selling or buying (or receiving notice that they or their spouse sold or bought) more than $1,000 in stocks, bonds, et cetera. Burr and Loeffler did this, which was how their sales became public.

But in fairness, they owed the public more than the legally required disclosures, filed 30 days after the sale.

If Burr, who has a reputation in the Senate as a day trader, really was selling his stock based off real fears grounded in public information, he probably should have said as much at the time. At the very least, he should have been immediately forthcoming to avoid the appearance of insider trading.

In any event, senators shouldn’t be “day traders.” Regularly buying and selling stocks presents them with too many opportunities for graft, appearances of impropriety, or ways to get rich off their knowledge — public or not.