One thing about this scenario is that the real interest, ceteris paribus, is raised from 3% to 5%. This by itself reduces demand for money and should reduce investment. The company isn't borrow at 3% anymore. It pays that 3% to bondholders and 2% to the bank; they aren't going to keep it in cash. So now, you are back to 1% interest rates for a triple A seller, and bond buyers only willing to sell at 3%.
Another affect that we discussed is the fact the bond owners and cash holders will maintain their positions rather than sell which furthers the reduction of money supply and raises interest. This will create a deflationary spiral due to Higher real interest rates. A bigger point is that money is that this sends the market into an uncertain future with a small handful of people deciding what interest rates should be. This is the opposite of free markets. There are several effects here that economics can't answer as to which ones are going to dominate in this scenario.
Looking back at the late 70's, you had the opposite problem which is too large to include here. However, the central bank looked at the problem as a traditional trade off between output and inflation. They tried to spur growth by increasing the money supply but only ended creating inflation. One reason for this is single digit inflation isn't an inhibitor to growth. The issue with this policy was that markets didn't respond to the Fed's actions the way the models say. Bond markets sold off and so the Fed increase M again and again because they were looking at the nominal interest rate. If they had been looking at the Real, history might be different. That is the disaster of a small group of people deciding what prices and the discount factor should be. In other words, central planning sucks and always will.
Central planning certainly sucks. I was just now reading about Thomas Jefferson -- he had the foresight to oppose the central bank which is the institutional cornerstone of the bank-politician alliance designed, really, to extract wealth from the rest of society. Who gave these people the right to plan our economic lives anyway? It might not be surprising that, after the central bank was dismantled by Andrew Jackson, and a rising USA threatened to become a major force outside the modern world system, Britain sided with the Confederacy in the Civil War, even though Britain had abolished slavery a few decades before.
I'm absolutely opposed to granting negative-interest power to the elites.
Real interest is nominal interest minus inflation. So in our example, let's suppose inflation was 0% (just randomly), the real interest would be 3% for those corporate bonds. The authorities could drag safe-money interest arbitrarily low -- and the lower that gets, the higher inflation should be, since people will want to circulate money in the economy rather than hold it. So the real interest could be made as low as the authorities want, in theory. (The company pays the 3% but will try to avoid the 2% by pushing its purchases forward -- this is the inflationary effect.)
It's true that existing bonds would become more valuable the lower the central bank sets the rates. But bonds eventually mature, and anyway these holders could cash in their winnings immediately by selling their bonds. Unless they bet on rates going lower during the life of the bonds, selling vs. holding would be a neutral decision. Cash owners would tend to part with their cash since they're losing cash as it sits in the bank. The authorities would have the power to make them lose more, if the current policy doesn't achieve the desired effect.