Whether one believes the fall in the value of sterling is a long-term change, or just part of a cycle, the question on all investors' minds is how this affects companies, particularly those with high levels of exposure to the US dollar.
First, the cumulative rise in the FTSE 100 is down to the fact that many of those companies earn a chunk of their revenues in US dollars, which neutralises the effect from any costs they incur in that currency. But constituents in the FTSE 250, for example, tend to buy more products or services in US dollars before selling them domestically in sterling. That leads to a considerable shortfall based on the exchange rate, sending costs higher than what's planned.
The value of sterling has dropped to a fresh 31-year low against the dollar and six-year low against the euro. And that presents a challenge for many companies trading on the London Stock Exchange. Sports Direct (SPD) was forced to issue a profit warning in the wake of sterling's latest dramatic fall, admitting that events had crystallised an exchange rate of 1.19 - instead of the 1.30 accounted for - resulting in a £15m hit to FY2017 cash profits.
The effect on other retailers is similar. Plenty of Britain's big brands - from Next (NXT) to DFS (DFS) to Laura Ashley (ALY) - source stock in US dollars and euros, only to earn the majority of their revenues in pounds. That means they pay more for goods, which aren't worth as much when it comes to selling them. This can be offset by increasing prices, thus passing the cost onto consumers, but a retailer's flexibility to do this in a deflationary environment is limited.
Some companies have cited a more positive result from sterling's weakness. Amino Technologies (AMO) earns mainly in dollars and, as such, management believes revenues and adjusted profits will exceed market expectations for the year ending 30 November 2016. The same is true for online pure-plays such as Boohoo (BOO), who find themselves "naturally hedged" thanks to a more 'multi-territory' - and therefore multi-currency - business model.
