For UK investors, a Stocks and Shares ISA makes a lot of sense. But one of the most important questions is what to put in it.

There are all kinds of opportunities in the FTSE 100 and the FTSE 250. So here are a few I think are worth investors following closely.

Rentokil Initial

I own shares in Rentokil Initial (LSE:RTO) in my ISA. And it’s fair to say the stock has done pretty well for me since I bought it. 

In an uncertain world. I think it’s one of the FTSE 100’s most predictable businesses. Demand for pest control isn’t going away any time soon.

The company’s balance sheet has been a concern recently. It acquired a big competitor in the US and took on a lot of debt in the process. Things, however, have been moving in the right direction recently. And if this continues, I think the stock could still do very well.

Boring businesses don’t always get the attention they deserve, which is fine. But Rentokil is definitely one investors should keep an eye on.

Target Healthcare REIT

Target Healthcare REIT (LSE:THRL) owns over 90 care homes across the UK. It makes money by leasing these to private operators. 

This is an industry where demand should be strong for some time. Put simply, people are living longer and that’s likely to increase the need for care.

The stock comes with a 6% dividend yield, which is pretty attractive. It means a £1,000 investment could return £60 in cash directly to investors.

Investors should note that regulation means the firm could be forced to incur costs if standards change over time. That’s one of the key risks. While this isn’t under Target’s direct control, it has been trying to prepare for this. And it’s done this by focusing on high-quality assets.

Attempting to stay ahead of any changes is the best thing the firm can do. So I think it’s an interesting business in a promising industry.

Compass Group

Compass Group (LSE:CPG) is a name a lot of investors won’t have heard of. It’s a FTSE 100 contract catering firm. 

While the name might not be familiar, it’s the industry leader. It’s bigger than both of its nearest two competitors combined. That size and scale gives Compass a big advantage. It means the firm has lower costs and can charge customers lower prices.

Despite being the leader, the firm only accounts for 15% of the global food services market. And that leaves plenty of scope for growth. 

Most of the firm’s sales come from the US (which is why its share price is listed in dollars). And that makes a recession over there a real risk.

Despite this, I think this is one for investors to take a closer look at. The more I find out about this business, the more I like it. 

Get it right

I think all three of the companies I’ve listed here are worth considering for a Stocks and Shares ISA. But investors don’t have to rush.

The important thing is to look at the businesses properly and build an informed view of them. That’s the key to investing well.