LONDON (Reuters) - Xilinx (XLNX.O) doubled its cash conversion ratio (CCR) in 2018, which the foundry said was due to growing demand for mobile processors and growth in the oil and gas industry.

The company on Thursday reported a CCR of 100 percent, meaning all of its net cash generated by operating activities was converted into cash after investments.

In the third quarter of 2018, the ratio was 72 percent.

Xilinx has committed to return 40 percent of its free cash flow to shareholders, said Byron Kelley, the company’s chief financial officer.

While Xilinx reported fourth-quarter revenue growth of 3 percent and an adjusted net income of $217 million, the company projected a lower-than-expected 2019 revenue.

The stock fell more than 9 percent in after-hours trading.

Xilinx reported a 37 percent increase in net cash generated in 2018 to $2.73 billion.

The company said it expects to report revenue in the range of $1.66 billion to $1.76 billion for the first quarter of 2019, below the $1.78 billion analysts were expecting.

The company reported diluted non-GAAP earnings per share of 66 cents, up from 46 cents in the fourth quarter of 2017 and above the 67 cents the company reported in the previous quarter.

While Xilinx’s annual reported revenue grew from $1.47 billion in 2017 to $1.66 billion in 2018, the company’s annual estimated revenue in 2019 is $1.69 billion, below the $1.76 billion analysts forecast.

Profitability in 2018 deteriorated, falling from a 2015 peak of 40 percent to 32 percent last year, according to Thomson Reuters I/B/E/S.

In an analyst call, Kessler said declining profit margins were attributable to Xilinx’s 2019 revenue projection, which at the midpoint of $1.68 billion falls short of the average of analyst estimates for 2019 revenue of $1.775 billion.

“There’s always the possibility that our estimate is overly optimistic, but it certainly doesn’t appear to be overly pessimistic at this point,” Kessler said.

Berenberg analyst Nick Heymann said of Xilinx’s forecast, “We don’t expect most of this to happen, as the market for mobile applications is not likely to remain as hot as it was last year, but we do think you could see mobile market revenues decline at low single digit rates.”

In December, Xilinx reported that its fourth-quarter mobile application processor business grew 15 percent sequentially.

The company said in November that it had a market share of 9.8 percent in fourth-generation mobile application processors, about one percentage point more than the company reported a year earlier.

(This story corrects source of CCR figure in fourth paragraph)