According to CNBC:

The indictment relates to "securities of Innate Immunotherapeutics ... an Australian biotechnology company on whose board of directors Christopher Collins served," the DOJ said.

Collins was one of Trump's first backers in Congress.

This story has just broke and will be updated.

Update #1:

The indictment can be viewed in full here.

Update #2

As mentioned above, Collins was the first member of Congress to endorse Donald Trump as President. Here's video of that endorsement.