(Reuters) -Traders on Wednesday added to bets the Federal Reserve will start easing in September and go big when it does, even after Fed Chair Jerome Powell said policymakers are not thinking about a 50-basis-point interest rate cut "right now."

Rate futures contracts continue to center around expectations for a more usual 25-basis point cut in September to start a series of rate reductions that could last into next year.

But as Powell during his post-meeting news conference repeatedly said the central bank has room to respond if the labor market unexpectedly weakens, markets began a turn.

Rate futures prices now reflect about a 17% chance of a 50-basis point rate cut in September, versus about 5% before Powell began speaking. Prices also reflect increased confidence the Fed will cut a total of 75 basis points over its final three meetings of the year, most likely in 25-basis-point increments, bringing the policy rate down to a 4.5%-4.75% range.

The Fed at its policy meeting ending on Wednesday left its key interest rate unchanged in the 5.25-5.50% range, as expected.