Beechjet 400 pilot reported failure of primary trim system on takeoff. Crew returned to departure airport and landed with no issues.

Narrative

I was the PIC for the flight but was the pilot monitoring. The SIC (Second in Command) was pilot flying. We were cleared for takeoff from runway XXR out of ZZZ. The before takeoff checklist was completed. Takeoff was a non event. Climbing through 500 feet. The SIC was trying to trim the aircraft. He was pushing the control stick full forward to lower the nose. He mentioned that he is having trouble trimming the aircraft. I started to help to push the nose forward as well and began to troubleshoot the issue. We determined the issue was the primary trim was stuck. We switched to emergency trim and leveled off at our assigned altitude. We then notified ATC that we are working an issue and will need a few minutes to troubleshoot. The SIC was hand flying the plane and I was running the radios and running the checklist. Then I ran the numbers for the return back to ZZZ. We got setup for the approach then vectored to the ILS XXR using the emergency trim and hand flying. Landed the aircraft with no issues. Cause: Failure of the primary trim Suggestions: Nothing that was in our control would have prevented this event.