Federal Reserve Chairman Ben Bernanke has a problem: how to wean markets from dependence on central bank stimulus. On Wednesday Bernanke did what some of his most dovish colleagues have urged for months. He laid out a clear path for how and when the Fed will bring its third round of bond-buying to a close.

It doesn’t take a master detective to figure out his solution – 7 percent.

“If the incoming data are broadly consistent with this forecast, the committee currently anticipates that it will be appropriate to moderate the monthly pace of purchases later this year, and if the subsequent data remain broadly aligned with our current expectations for the economy, we will continue to reduce the pace of purchases in measured steps through the first half of next year, ending purchases around mid-year,” Bernanke said in a press conference following the Fed’s two-day policy-setting meeting.

“In this scenario, when asset purchases ultimately come to an end, the unemployment rate would likely be in the vicinity of 7 percent, with solid economic growth supporting further job gains.”

Bernanke’s seven-percent solution has not elicited from markets the same “long sigh of satisfaction” that Sherlock Holmes emitted after shooting up in “The Sign of Four.”

Far from it: stocks tanked and borrowing costs – as measured by yields on U.S. Treasuries – soared.