The New York Stock Exchange has given Donaldson Co. a six-month extension to file its annual report for investors, time the firm needs to sort out an accounting problem in Europe.

But the stock exchange also warned that late filing means "that the company is not in compliance" with rules for being listed.

The Bloomington company, a maker of filtration systems for factories and large industrial vehicles, announced last month that it was unable to file its annual report with the Securities and Exchange Commission because of an ongoing investigation into the way revenue was reported for select gas turbine projects in Europe.

While the reported European contract amounts appeared to be accurate, some of the revenue was attributed to the wrong month, quarter or year, Donaldson said.

Last month, executives requested a 15-day filing extension that was to have ended on Wednesday. On Thursday, it announced that it missed that deadline and needed more time.

On Friday, the NYSE informed Donaldson that it will have six months to file the annual report, formally known as Form 10-K, with the SEC.

Donaldson, which generates about $2.4 billion a year in annual revenue, said it intends to regain compliance with the NYSE listing standards by filing the reports within the six-month extension period.

Donaldson has been wrestling with sluggish revenue growth in the wake of slowdowns in the global oil and gas, mining and agricultural-equipment industries.

Donaldson shares fell 1.4 percent, or 39 cents a share, Friday to close at $28.33.