Don’t hold your breath for a bigger pay raise next year. Despite an improving economy and jobs situation, American employers are tightening their belts.

Pay raises for US employees are not expected to improve next year, according to a survey released Monday by global professional services company Aon, based on a survey of over 1,000 companies. Base pay is expected to rise 3 percent in 2018, up slightly from 2.9 percent in 2017. Spending on variable pay — incentives or bonuses — will be 12.5 percent of payroll, low levels not seen since 2013. This suggests a “pessimistic view of corporate performance in the coming year,” Ken Abosch, a strategy and development analyst at Aon, said in a statement.

“Companies remain under pressure to increase productivity and minimize costs,” he said. “As a result, we continue to see relatively flat salary-increase budgets across employee groups, with most organizations continuing to tie the majority of their compensation budgets to pay incentives that reward for performance and business results.” Middle-of-the-road performers will lose out: 40 percent of companies said they’re reducing or eliminating increases for lesser performers.

Incentives and bonuses vary by city and industry. They will account for 14.7 percent of the payroll for companies in Houston, 14 percent in New York City and 13 percent in Philadelphia. Workers in the automotive industry will see higher-than-average base pay increases this year (3.2 percent), along with those who work in computers (3.2 percent), accounting, consulting and legal fields (3.3 percent) and telecommunications (3.2 percent). But workers in education will see base pay raises of 2.7 percent, along with 2.8 percent raises in construction, engineering and the medical device industry.

The US economy added 156,000 jobs in August, compared with the 170,000 predicted by economists polled by MarketWatch. The unemployment rate ticked up by a point from July to 4.4 percent in August, shy of expectations of 4.3 percent. And yet salaries effectively remain stagnant for millions of American workers, despite the lowest unemployment rate in 16 years, with hourly pay rising 2 percent per year since the Great Recession. Economists point to higher-paid baby boomers retiring, lower productivity and management skittishness since the recession.

The C-suite has not experienced such belt-tightening, however. The median total compensation for CEOs at S&P 500 companies totaled $11.5 million last year, an 8.5 percent increase from the previous year and the largest increase since 2013, according to a joint report by the Associated Press and the executive pay data firm Equilar released earlier this year. Not accounting for inflation, CEO pay spiked 19.6 percent, helped by a buoyant stock market.

What’s more, the average CEO of an S&P 500 company made 347 times more money than the average worker, according to separate data released by Executive Pay Watch, in a report conducted by the American Federation of Labor and Congress of Industrial Organizations. Last year, CEOs were paid 335 times the average worker. The average production and non-supervisory worker earned $37,600 annually in 2016. “When adjusted for inflation, the average wage has remained stagnant for 50 years,” the report said.