2 choices that can boost a Stocks and Shares ISA

Over the past ten years, the average annual return from a Stocks and Shares ISA has been 9.64%. That’s a great result for investors, but achieving it isn’t entirely straightforward.

An ISA offers tax protection on dividends and capital gains, but it’s not a magic ticket to investment returns. Identifying which stocks to buy is still essential for supercharged returns.

Please note that tax treatment depends on the individual circumstances of each client and is subject to change in the future. The content of this article is for information purposes only. It is not intended to be, and does not constitute, tax advice of any kind. Readers are responsible for conducting their own due diligence and seeking professional advice before making any investment decisions.

Apple

At the top of my list of shares I want to buy (and already own) to bolster an ISA is Apple (NASDAQ:AAPL). I believe the iPhone maker will be a major beneficiary of the rise of artificial intelligence (AI).

The company benefits in two ways. First, I expect AI developments to boost iPhone sales, as the latest releases have strong consumer demand.

Second, Apple’s dominant position in the smartphone market puts it in a powerful position. The likes of Microsoft And Alphabet must go through the entire ecosystem to reach as many customers as possible.

The biggest risks for investors are twofold. The first is antitrust – I don’t see any competitors disrupting the business, but there is a real chance that the authorities will break up the walled garden.

The second is China. Apple’s presence in the country is significant, both in terms of production and customers, and tensions with the US have already begun to create problems for the company.

Despite the risks, both the stock and the company have performed very well over the past five years and I expect this to continue, which is why I am looking to expand my investment.

Porvair

With a market capitalisation of £311 million, the British manufacturer Porvair (LSE:PRV) is at the other end of the scale in terms of size. But it is another share I might buy for my ISA.

The stock price has been up and down a lot lately, but the underlying business has been growing steadily. And I think there is more to come from the company.

Porvair filtration products have key features that generate repeat business. The aerospace filters are specified in the design of airframes and the laboratory equipment is disposed of after each use.

This makes the company difficult to compete with and puts it in a strong position to generate long-term revenue growth, which is why I want to buy the stock.

The end markets the company sells into can be cyclical. Demand for aerospace plummeted during the pandemic, and lab equipment has been burning through excess inventory ever since.

That does bring a risk of short-term volatility in sales and profits. But I think the company will do well in the long term, and so I see it as a share that can boost returns from an ISA.

Growth stocks

Both Apple and Porvair are growth stocks. I expect that they will both use the profits they are generating now to significantly increase their earnings per share in the future.

Furthermore, the underlying companies have dominant market positions that are difficult to disrupt, so I think both could be great long-term investments for my Stocks and Shares ISA.