A third of employers giving bonuses to the poorest performers

For the fifth year in a row, bonus payouts will fall short of what employers had budgeted for, according to a Towers Watson survey of 170 large and midsize U.S. employers. The 2015 projected bonus funding for companies is, on average, 89 percent of the performance target. That's down from 93 percent last year.

But here's the thing: Towers Watson says "three in ten employers still plan to give bonuses to workers who failed to meet performance expectations." That is the highest percentage since 2007, and a jump from last year's 28 percent.

Putting aside companies that give all workers the same bonus, companies that differentiate give their lowest performers about 65 percent of the target payout, on average. Employees who exceed performance expectations get bonuses about 19 percent above target.

Just 3 percent of employees downright failed to meet performance expectations, according to Towers Watson. But a solid 8 percent only partly met expectations and a hefty 56 percent met them but failed to exceed (25 percent) or far exceed (8 percent) expectations. That's a lot of bonus dollars for disappointing and middling employees.

Is it a remnant of corporate largesse? A fear of losing skilled workers to the competition? A bit of managerial laziness?

Most programs are designed so that if an employee doesn't meet performance goals, they get either a smaller bonus or no bonus, said Towers Watson's director of rewards consulting, Sandra McLellan. But over time, she said, some companies have simply "lost clarity about the purpose of their [bonus] programs."