Should you buy the FTSE 100 at 6,900?

Cases of vertigo are on the rise this summer. I know that because the FTSE 100 has added over 1,100 points, or 20%, since the lows posted in the immediate aftermath of the Brexit decision. That's simply gobsmacking. Also up 9% from pre-referendum levels, investors are rightly asking whether they should keep buying or cash in. The answer, unfortunately, is not straightforward.

Volumes typically tail off over the summer and, although Brexit and huge monetary stimulus programmes have piqued interest this time, the City's big decision-makers are out of town. Their juniors in the hot seat certainly won’t be making major market calls while the boss is baking in the south of France.

This means further volatility, and recent gains imply that the bulls still have it. But what about ordinary investors, especially those, like myself, that have had their fun in the sun and are now back at the coal face?

Well, despite the market rally - remember, the more domestic-focused FTSE 250 is also within sight of a record high - there is value out there, and high yields, too. The more international FTSE 100 currently yields just under 4% and a simple stockscreen tool will throw up plenty of quality companies paying generous and safe dividends to shareholders.

Income-seekers have been chasing yield since the financial crisis stripped interest rates away to almost nothing. Savers bothered to get the best return on their money also switched into equities. Brexit and the latest cut in borrowing costs - expect another trim in a few months - plus further monetary stimulus only underpins the argument for share buying.

Will Brexit pull the rug away? Hard to say right now, but it would be short-sighted to think we've got away with it completely. Brexit will have a big impact on the UK economy, it's just too soon for the evidence to be conclusive.

Chief executives say as much. Recent outlook statements during reporting season are littered with references to "caution" and "too early to tell".

It's never wrong to take a profit, but the market's not about to fall off a cliff - yetEven recent economic data only tells us part of the story. We hear today that retail sales were better than forecast in July, but shopkeepers anticipate a bad August. Consumer confidence is also tipped to wane, especially once the summer's over and people take a look at what's left in the bank account after the holidays. Any post-Brexit impact on the labour market will only serve to further slow household consumption.

So, to keep buying or cash in? Well, 6,900 is a long way up, and the devil on my other shoulder keeps whispering "it's never wrong to take a profit". It's not, but neither is the market about to fall off a cliff, yet. UK interest rates will stay low for years and governments will keep propping up markets as long as they can.

The weak pound means overseas earners still look a decent bet. Keep diversified, but businesses that will be around forever, supplying the things we use every day, will never go out of fashion.

This weekend we'll be asking regular contributors to Interactive Investor what they think.

This article is for information and discussion purposes only and does not form a recommendation to invest or otherwise. The value of an investment may fall. The investments referred to in this article may not be suitable for all investors, and if in doubt, an investor should seek advice from a qualified investment adviser.