Johnson Matthey promises investor return in absence of acquisitions

* Q1 underlying pretax 94 mln stg vs year-ago 95 mln

* Expects up to 380 million pounds from disposals

* Flags poss 10 mln stg impact from adverse platinum, forex moves

* Shares (Frankfurt: DI6.F - news) down 2.8 pct (Adds analyst comment, lower profit warning details, shares)

By Silvia Antonioli and Clara Denina

LONDON, July 22 (Reuters) - Johnson Matthey (LSE: JMAT.L - news) , the world's biggest auto catalysts maker, pledged on Wednesday to return cash from the sale of two businesses to shareholders in the absence of major acquisitions.

The move came as the UK-based company reported a slight fall in first-quarter profit and warned full-year earnings could be negatively impacted by 10 million pounds ($15.6 million) due to adverse platinum and currency price movements.

Its shares were down 2.8 percent by 0936 GMT having fallen to not far from a near nine-month low set earlier this month.

Johnson Matthey, which makes most of its profits from the sale of platinum-rich catalysts, has benefited in recent years from tighter European regulation on emissions, boosting demand for more value-added catalysts.

Its market dominance however is being challenged by competitors such as Belgium's Umicore and its precious metals products division is suffering from a plunge in prices.

The group expects to receive up to 380 million pounds ($593 million) from the already agreed sales of its Gold and Silver (Shenzhen: 300221.SZ - news) Refining and Research Chemicals businesses.

"I'd expect a reasonable proportion of that to be returned but this depends on whether we enter any material M&A," Finance Director Den Jones said in an interview, adding the company would look at opportunities in fine chemicals and new businesses.

"Even (Taiwan OTC: 6436.TWO - news) if we do return some cash ... the balance sheet remains in the position to support an acquisition of around 200 to 300 million pounds," Jones said. "But with material M&A, of around 500 million pounds, we would not have the ability to return capital."

To counter worries over the falling market share of platinum-rich diesel vehicles in Europe, the world's biggest market, the company is betting on its newly acquired battery business and does not rule out acquisitions in the sector.

But analysts warn that the company should look at diversifying its battery technology portfolio in coming years.

"Johnson Matthey's eggs are in one basket in terms of battery materials, as they are currently exposed to lithium (based) battery," Liberum analyst Adam Collins said, noting the auto industry had mostly invested in cobalt-based chemistries. "At this stage they have no positions in this space."

The company posted an underlying pretax profit of 94 million pounds for the quarter through June versus 95 million a year ago.

It was hurt by plunge of about 10 percent in platinum price, as well as by weakness in its Process Technology division, which sells catalysts and technologies to the oil and petrochemical sector.

($1 = 0.6407 pounds) (Editing by David Holmes)