When one steps back from the excitement, it's hard not to think of the current ASX share market as a greedy one. After all, the S&P/ASX 200 Index (ASX: XJO) has appreciated by over 15% since the beginning of November last year and hit several new all-time highs in the process.

It's normal for the markets to occasionally hit new highs of course. But it is not normal for the ASX 200 to gain over 15% in just five months or so. In fact, it's unusual to see that kind of rise over an entire year.

Unfortunately, analysts at Macquarie believe that these gains are unlikely to last. As reported in the Australian Financial Review (AFR), Macquarie strategists Matthew Brooks and Sophie Bolton have built a new FOMO (fear of missing out) Meter, which is designed to gauge investor sentiment on the US markets, and whether it is being overly influenced by emotional whims. That would be fear or greed.

This Meter is reportedly constructed using seven different indicators, including the VIX volatility index and measuring how many stocks on the S&P 500 Index are above their 200-day moving averages.

Their verdict of the current market is sobering: "We continue to believe that sentiment needs to cool a little and that investors should wait for a correction before rotating more to risk".

They go on to point out that this might mean that US returns from shares will be "below average" and that ASX shares could deliver a "slightly negative return".

Brooks and Bolton have a potential solution for this conundrum: focus on defensive ASX shares. Pointing out that sectors like tech stocks and consumer discretionary shares tend to rise and fall alongside investor sentiment, the analysts instead recommend investors look to more defensive plays while the market is still hot.

They have four shares in mind for this endeavour. The analysts name packaging and logistics company Brambles Ltd (ASX: BXB), grocer Coles Group Ltd (ASX: COL), healthcare stock ResMed Inc (ASX: RMD) and real estate investment trust (REIT) Goodman Group (ASX: GMG).

Brooks and Bolton point out that these four stocks reported positive earnings during the recent reporting season, and all currently enjoy outperform ratings from Macquarie.

They also suggest that investors might want to take a look at Woolworths Group Ltd (ASX: WOW), Telstra Group Ltd (ASX: TLS), Endeavour Group Ltd (ASX: EDV) and Orora Ltd (ASX: ORA) as more "adventurous" defensive ASX shares.

So an interesting insight from these Macquarie analysts. It will be interesting to see if these FOMO Meter predictions are indicative of what happens next on the share market. As with all investing forecasts, they will only be obvious in hindsight