Corporate share buybacks are on the rise, but that may not be a good thing.

Companies in the Russell 3000 stock index repurchased $567.6 billion of their own stock last year, a 21 percent jump from 2012, Rob Leiphart, an analyst at Birinyi Associates, told The Wall Street Journal.

But companies haven't historically been adept at timing their purchases, writes The Journal's Jason Zweig. "If you wanted a signal of when to get in and out of the market, doing the opposite of whatever companies themselves are doing would serve you pretty well."

Editor's Note: 18.79% Annual Returns ... for Life?

Companies should buy back their shares when they're cheap and the money couldn't be better used on capital expenditures or acquisitions, Zweig says.

"Yet companies tend to exhibit the same perverse timing—buying high and selling low—as individual and institutional investors."

To be sure, companies haven't reached the heights of 2007, when share buybacks totaled a record $728.9 billion, led by banks that were soon to collapse, Zweig says.

But, "if companies end up chasing their own shares as high as they did in 2007, a fall to earth might not be far behind," he writes.

Some experts say share buybacks will slow down, as investors demand improvement in corporate performance instead.

"People are starting to wise up: McDonalds and IBM have done [buybacks] for years, but shares have stagnated," Paul Nolte, portfolio manager at Kingsview Asset Management, told MarketWatch. "People want to see real earnings, real sales."