Should you buy or sell these shares after today’s updates?

July was a hectic month for first-half results, and though things are slowing a bit through August, we still have a news-packed week. Here are three firms making the headlines today.

Growth story?

Shares in Dialight (LSE: DIA) rose by 2.6% in morning trading, to 579p, on the back of a pleasing set of first-half figures. Revenue actually fell slightly, but underlying operating profit came in at 2.5 times the same period last year, or £4.2m, although there was a statutory pre-tax loss of £7.1m as the firm emerges from its turnaround plan.

Underlying EPS picked up by 44% to 7.8p, and the firm turned an £8m net debt at the H1 stage of 2015 into net cash of £7.2m. Chief executive Michael Sutsko spoke of greater revenue visibility with second half orders up 10%, and told us the board is “confident of making progress this year and beyond“.

After a couple of erratic years, the LED technologist is forecast to boost EPS by 49% this year as Mr Sutsko said expectations are unchanged. That would put the shares on a P/E of 29, but a further 60% in earnings growth pencilled-in for 2017 would drop it to 18, and we have likely PEG ratios of 0.6 and 0.3 for this year and next. Dialight could be an attractive growth opportunity.

Big drop

Rotork (LSE: ROR) shares had been picking up strongly with a 40% climb since late February until Monday’s close. An 8.6% drop to 195p has taken the shine off that a little on the occasion of the company’s first-half update. The firm, which makes valve, sluice gate and damper actuation products for the oil, gas, power and waste industries, reported falls across the board. Revenue is down 3.7% to £263.9m, with adjusted pre-tax profit down 21.8% to £50.1m and adjusted earnings per share down 21.9% to 4.25p. But at least the interim dividend was maintained at 1.95p per share.

The slump is largely down to the depressed oil price, which has now fallen back below $40 per barrel again, and the knock-on effect on orders from the oil and gas business. According to chief executive Peter France, full-year margins should be lower than 2015’s as he said that “activity in the oil and gas markets will remain subdued, and the timing of order placement will be difficult to forecast“.

Rotork will almost certainly do better when oil finally gets back to more profitable levels, but in the meantime a forward P/E of 21 looks demanding to me.

Marketing magic

Direct marketing firm 4imprint Group (LSE: FOUR) has seen its shares more than double in two years and six-bag in five. Against that a modest 1.3% rise to 1,498p on the day of first-half results might not be too exciting. But the figures do look good — revenue is up 17% to $270.2m with underlying pre-tax profit up 18% to $14.3m and underlying EPS up 19% to 37.28 cents. The interim dividend was lifted 35% to 16.32 cents (or 59% to 12.3p thanks to the drop in sterling).

The bulk of the firm’s revenue comes from North America, so there’s no real Brexit risk here. So with a solid record of rising earnings and two more years of growth forecast this year and next, is it too late to buy the shares? Well, we’re looking at P/E multiples of around 20 with PEG ratios above one, and that suggests the super-bargain days are behind us.

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Alan Oscroft has no position in any shares mentioned. The Motley Fool UK has recommended Rotork. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.