When the market wobbles, it can be unnerving. Over the past few months, we have seen the market more than merely wobble. The US S&P 500 entered market-crash territory, although it has since recovered some ground. The UK market has been seeing a fair bit of turbulence too. But I view that as a potential bargain-hunting opportunity and have been looking for shares to buy for my portfolio.

During stock market turbulence (and at other times too) though, it is important for investors to remember a key distinction: price and value are not the same thing.

Learning from Warren Buffett

That may sound like an academic difference, but it is a highly important one. Ignoring it can be very costly for an investor. As legendary investor Warren Buffett sums it up: Price is what you pay and value is what you get”.

To illustrate, imagine a share sells for £1 and then crashes to 50p. Is it a bargain? Without knowing the details of the business, it is impossible to say just based on share price.

Why? Maybe the share was worth £1, which is why it was previously selling for £1. So 50p is a bargain. Maybe it was only ever worth 25p, so it was not a bargain at £1 and is still not a bargain despite losing half of its value (this describes the common investing mistake of buying a value trap).

Or maybe the share was worth £1 but the price crash was because a change in its business prospects meant it was no longer worth that – or perhaps even 50p. That scenario pretty much sums up the position of many banking shares during the 2008 financial crisis. Yes, Lloyds has risen 126% over the past five years – but it is still 76% below its 2007 highpoint before that crisis.

On the hunt for bargains

I aim to remember that as I update my list of shares to buy during stock market turbulence. For example, I have been eyeing Nvidia for a while and its share price has lately traded lower.

But a lower Nvidia share price partly reflects that fact that trade conflicts risk hurting the firm’s profits. Therefore, despite the price fall, I do not yet think Nvidia offers me the value I am looking for.

So which companies have made it to my list of shares to buy? One recent example is value retailer B&M (LSE: BME).

The B&M share price is down 34% over the past year. But it has lately been staging something of a turnaround, with the shares up by a third in less than two months.

While stock market turbulence and a weak economy could be bad for many companies, I actually see them as potentially positive for this ‘pile ‘em high, flog ‘em cheap‘ merchant. Tightening consumer purses trings could help B&M take market share from more expensive rivals.

One risk is B&M’s ongoing hunt for a chief executive. Not having a leader in place can lead to a business drifting and important decisions being postponed.

But the company has a proven business formula, lots of white space to expand both in the UK and on the continent and its ongoing shop opening programme could build revenues. I see it as worth considering.