The diversified and global nature of Bunzl’s (LSE: BNZL) operations has long made me take a bullish view on the firm’s long-term earnings outlook. Having said this, however, I reckon the firm’s share price could be set to endure some volatility, with the next trading update — quite likely in the coming weeks — possibly providing the downward catalyst.

It would be foolish to ignore recent trading updates from Bunzl’s FTSE 100 (INDEXFTSE: UKX) outsourcing peers Capita and Mitie, both of which have described tough trading conditions in the wake of Britain’s EU referendum.

Last week Capita slashed its profit forecasts to £535m-£555m for 2016, down from its previous estimate of £614m. And Mitie advised in mid-September that it expects “operating profit to be very significantly lower” for the period spanning April-September, the company citing uncertainty surrounding June’s Brexit vote and the prospect of lower UK growth rates.

Bunzl’s fortunes aren’t as dependent on a healthy domestic economy as those of Mitie or Capita — the company sources just 15% of revenues from Britain, after all. And that helps me to maintain my bullish long-term take on the firm.

But that’s not to say a poor performance here in the UK won’t hammer investor appetite given the negative press surrounding its sector rivals. Bunzl has already announced that home sales had dipped 3% during January-June.

And I believe signs of additional pressure could cause many to question the firm’s high ‘paper’ valuation of 23 times, and prompt some heavy sentiment-driven share sales.

Out of gas?

I’m far more cautious over Centrica’s (LSE: CNA) share price prospects, in both the near-term and beyond, and reckon the energy giant’s upcoming market update (scheduled for Thursday, 15 December) could prompt a painful reversal.

Centrica has been unable to stop the steady decimation of its customer base as smaller, promotion-focused independent suppliers have continued to spring up. Indeed, the number of British Gas residential accounts slipped again during the first half, a 3% decline resulting from “long-term contract roll-offs and increased competitive intensity.”

On top of this, I believe the huge oversupply washing over the oil market could also put the profitability of the firm’s Centrica Energy arm under close scrutiny.

Crude values have spiked back above the $50 per barrel mark in recent days thanks to a tentative output freeze agreement from OPEC. However, doubts persist over whether this accord will hold as individual country quotas are yet to be designated, and members Iran, Nigeria and Libya have been exempt from reducing their own production.

Any failure to rubber-stamp the agreement at November’s meeting could send oil values rattling lower again, and with them Centrica’s share price.

Sure, Centrica’s forward P/E rating of 15 times may be bang in line with the big-cap mean. But I reckon this value still fails to adequately address the company’s high risk profile, and reckon December’s update may facilitate a fresh stock value decline.

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