This paper presents a novel high-frequency motive classification strategy - the Trading Markov Sign Restriction (TMSR) - to map pure monetary policy and central bank information motives onto monetary surprises. It considers high-frequency dynamics on the interest rate futures and the stock market and examines systematic phases of expectation adjustment behaviour within 30-minute windows around policy announcements. I show that three systematic phases of expectation adjustment intensities can be observed for monetary policy announcements from the Swiss National Bank (SNB). Based on these identified phases, trends in trading directions on the interest rate futures and stock market are then weighted by a measure of expectation adjustment intensity to classify pure monetary policy and central bank information motives per policy announcement. Studying the effects of pure monetary policy and central bank information surprises reveals that both types of surprises affect financial assets; however, for the Swiss case, these effects differ from each other only for the exchange rates and stock market responses.