Given the grim economic news across the Atlantic, the last place people might want to put their £7,000 annual individual savings account (ISA) allowance would be in a fund investing in America.

But there is at least one good argument for looking to the US – the current weakness of the dollar. Investing in the US involves a degree of currency speculation: when an investment is bought, pounds are converted into dollars; when sold, the reverse happens. If in the interim the dollar increases in value against the pound, that automatically increases returns.

Short-term speculating on currency movements is a game for the experts and even they often get it wrong. But economists insist that the pound cannot remain at its current elevated level for ever. In short, there is a good chance UK investors in the US will benefit from a strengthening dollar.

Download the new Independent Premium app Sharing the full story, not just the headlines

However, any bonus from currency moves could be offset if the fund itself performs poorly. So the question remains: is this the right time to be looking stateside?

Tom Walker, who runs the US fund at fund manager Martin Currie, says: "There has been a lot of poor economic data and people are understandably worried. But we don't believe the US will lag behind for ever. What you have to remember is that this is a very dynamic market with some of the best companies in the world."

Philip Shaw, an economist with Investec, is more cautious: "Sterling is fundamentally overvalued against the dollar. Over the next five years, it will have to fall back into line. But it would be difficult to say whether now is a good time to invest in US stocks."

Mark Dampier, research director at independent financial adviser Hargreaves Lansdown, warns: "Part of the problem is that it's so hard to find US funds with any sort of consistency of performance."

He rates the Martin Currie North America fund, Neptune's US Opportunities and, more debatably, Legg Mason's US Equity, which hasn't been faring well. "That fund has been really poor over the past two years or so, but good managers don't become bad ones overnight. It can be a good time to invest in a fund after it has had a difficult couple of years."

Overall, though, Mr Dampier is not sure now is the right moment to go into US shares. "Given all the credit problems, we haven't seen that much of a correction in share prices," he says. "I'd rather wait to see some real signs that things are starting to pick up."