The QE multiplier

Felix Salmon writes:

If you take the amount of tapering that the market expected yesterday, and the amount of tapering that the market expects today, what’s the difference, in dollar terms? In other words, by the time tapering ends, and the Fed is no longer engaging in quantitative easing, how much extra money will it have spent buying bonds, if current market expectations hold, compared to what the market expected on Wednesday?

Then comes the next question, which is this: how much did the value of US fixed-income assets rise on Thursday? And, for that matter, how much did the value of US stocks rise on Thursday?

I don’t know the exact answers to the questions, but I’m pretty sure that the latter numbers are much larger than the former — that the market reaction, in dollar terms, was hugely greater than the extra amount of QE that the market now expects.

If that is indeed the case, then what we’re seeing is what you might call the QE multiplier — the amount by which every dollar of QE effects the markets as a whole. I don’t know what we thought the QE multiplier was on Wednesday, but in light of Thursday’s market action we might need to revise our guesses: the QE multiplier is, I suspect, much larger than most of us would have pegged it at.

Unlike Felix, I am, these days, made nervous by the size of the QE multiplier.