Additionally, some growth stocks have famously delivered spectacular returns. AI chip maker Nvidia, for example, has skyrocketed 2,180% over five years and 20,470% across a decade!

Here, I want to consider how large a Stocks and Shares ISA portfolio could be after years of investing £700 a month into growth firms.

What are they?

Growth stocks are simply shares of companies that are growing much faster than the market average or their peers. If a listed business is consistently growing its annual revenue above 25% say, then it would normally be defined as a growth share.

Often, these stocks will be from the technology sector, but not always. Look at engine maker Rolls-Royce, which is now putting up very strong revenue and earnings growth in the double digits. The FTSE 100 blue-chip stock’s up 750% in three years!

Clearly then, growth firms can come in many guises, offering various avenues of growth for an ISA portfolio.

A cautionary tale

However, growth investing is certainly not without risk. Companies than can keep increasing their revenue and/or earnings in the double digits for long periods are rare beasts. As a result, many stocks that appear to be the real deal turn out not to be.

I’ve owned a handful over the years. One that sticks in my memory is Illumina (NASDAQ: ILMN). Shares of this gene-sequencing giant soared for many years, then started slumping as growth tailed off.

The stock’s down 83% since August 2021.

Illumina hasn’t done itself any favours in recent years. For example, it acquired biotech firm Grail in 2021 without securing the necessary regulatory approvals, which resulted in financial penalties, strategic setbacks, and a forced divestiture. Oops. 

Today, the US firm is under new management and is trying to reignite the growth engine. Perhaps it will bounce back.

However, it was recently put on China’s ‘unreliable entity’ list of foreign firms. So it could face fines and restrictions in a long-term growth market that represents 7% of revenue. Not ideal.

Fortunately, I managed to sell my Illumina holding in 2022 before most of the share price damage was done. But it serves as a cautionary tale of what can go wrong and why companies need to be monitored closely.

How much?

The key to minimising such risks is to build a diverse portfolio. Despite disappointments like Illumina, my portfolio has benefitted from growth stocks such as Axon Enterprise, Intuitive Surgical, MercadoLibre, Shopify, and Games Workshop. All have been market-beaters.

There’s no specific rule on the number of stocks to own. But I would say 20-30 holdings is a good target, certainly for new investors.

Through such diversification, I reckon an 11% average return is achievable long term. That’s not guaranteed though, as it’s above the market average. But with sound stock research and consistency, such a return is not beyond the realms of possibility.

With this rate of return, someone investing £700 a month would go on to build a £1m ISA portfolio after 25 years. Starting from scratch, that would be some achievement.

The post How much could an ISA investor make putting £700 a month into growth stocks? appeared first on The Twelfth Magpie.

A great British exporter

The first stock I don’t plan to sell is British spirits giant Diageo (LSE: DGE). The company has a portfolio of over 200 brands sold in 180 countries.

Diageo’s most popular brands

Most of these brands have a timeless quality to them, though, of course, the risk of a recession is looming. While this could hurt sales of alcohol, consumers tend not to cut back on their favourite tipple even during recessions. And I think as disposable incomes rise in South-East Asia and Latin America, demand for Diageo’s products will remain strong for decades.

The DNA age

Illumina (NASDAQ: ILMN) makes gene sequencing machines that enable customers to read and understand an organism’s DNA. The firm’s products played a crucial role during the pandemic, enabling scientists to identify novel coronavirus mutations, track transmission, and ultimately to develop vaccines.

The company commands 70% of the global DNA sequencing market. A very healthy 70% of its revenues are recurring, and its operating margins are around 20%.

This dominance, however, hasn’t gone unnoticed by regulators, and Illumina has been thwarted recently in its attempts to acquire competitors. The risk here is that if organic growth slows, it won’t be able to grow through acquisition.

Even so, with only 0.02% of humans sequenced today, Illumina has a gigantic runway of growth ahead of it. I believe we’re entering the DNA age and I intend to hold my shares over the long haul.

An ageing population

By 2050, the world’s population of people aged 60 years and older will double to 2.1bn. This trend towards an ageing global population is one of the reasons I own shares in Intuitive Surgical (NASDAQ:ISRG).

The company is the top dog in global surgical robotics, controlling around 80% of the market. Its flagship product is the da Vinci Surgical System, which surgeons use to perform an increasingly wide range of minimally invasive procedures.

Some of the benefits of robotic-assisted surgery for patients include less pain and blood loss, reduced risk of infection, and less scarring. Also, recovery times are quicker, saving health systems a fortune.

Today, over 10m procedures have been carried out on the company’s robotic-assisted devices, from an installed base of 7,364 systems. Once medical professionals are trained on these products, they’re unlikely to switch to a competitor.

The competitive advantage Intuitive Surgical now has over its rivals is enormous, but that doesn’t mean competitors couldn’t emerge one day with even better surgical systems.

Still, an ageing global population should drive demand for robotic surgery for decades. So I can’t see myself ever selling the shares. In fact, I’m thinking about buying more.

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Following the outbreak of Covid-19, medical institutions, pharmaceutical companies, and even governments are realising the importance and applications of genomics, both from a diagnostic and treatment perspective.

Consequently, analyst forecasts of the already $21.8bn genomics market predict immense double-digit 18.2% annual compounded growth over the next decade. After all, it could have a transformative impact on both medicine and diagnostics.

Needless to say, that could be a very lucrative opportunity. So, let’s dive into the details about investing in genetics shares.

What are genetics stocks?

Genetics stocks occupy a small section of the biotech industry. As the name suggests, these businesses focus on developing treatments for genetic diseases by repairing or replacing the faulty genes causing the problem.

The genomics industry isn’t particularly new and has been around for decades. But due to the high costs, commercialisation has been challenging and still remains that way today. However, thanks to recent technological advancements, development costs are falling drastically while simultaneously boosting accuracy. 

Therefore, it’s no surprise that research into gene therapy has accelerated, with potentially game-changing treatments entering clinical trials both in the UK and abroad.

Genetics shares can be categorised into three segments:

• Sequencing & analysis – Companies analysing genetic data to detect defects in patients
• Testing & diagnostics – Firms using sequencing data to diagnose genetic diseases
• Gene editing – Biotech groups developing gene therapies that eliminate defects in the genome sequence

While there is some overlap in each category, firms within their respective segments often have different target markets and don’t necessarily compete with each other. However, the level of competition within each category is rising as more businesses seek to capitalise on the massive growth opportunity.

Unsurprisingly, this level of growth comes with a high volume of risk. The medical industry is highly regulated, with each test, device, and drug required to meet rigorous standards. 

Drug development is particularly notorious for its difficulty. In fact, a study by the Biotechnology Innovation Organisation showed that only 9.6% of treatments that make it to phase one clinical trials actually reach the market.

So, it’s hardly surprising that most pure-play genetics stocks are exceptionally volatile. And in some cases, the failure of a clinical trial can be a death sentence for these businesses. But all it takes is one successful treatment to potentially unlock multi-billion-dollar annual revenues.

Top genetics shares in the UK

Let’s explore the top three UK genetics shares in order of market capitalisation as of January 2026.

Genus

Genus is a niche but world-leading genetics sequencing business that focuses on the animal agriculture industry. The company owns directly (and indirectly through partnerships) various herds of pigs and cattle.

Using its sequencing technology, the group tests and identifies key desirable traits among the herd, such as feed efficiency, disease immunity, protein and fat content, and fertility.

Management then generates revenue by selecting the animals with the strongest genetic profile for breeding with farmers’ herds. The end result is healthier offspring, lowering costs for farmers while simultaneously increasing the quality of the end product for consumers.

Oxford Nanopore Technologies

Oxford Nanopore was spun out of the University of Oxford in 2005. Since then, the business has become one of the UK’s largest genetics stocks, developing a proprietary DNA and RNA sequencing technology. It’s the first one of its kind to provide real-time data analysis and rapid testing.

This technology has been embedded into a variety of devices, which the group primarily sells to scientific researchers involved with clinical trials. However, management has also been broadening its horizon, targeting several applied markets. 

The list includes consumer healthcare with its Covid-19 rapid testing solution, agriculture by identifying superior plant genomes, and even the environment by analysing the microbial composition of glaciers.

More recently, with its Covid-testing segment unsurprisingly shrinking, the business primarily sells life-science research tools like DNA and RNA sequencing solutions (MinION, GridION, and PromethION platforms,) driving more consistent revenues and cash flows.

OXB

OXB (formerly known as Oxford Biomedica) is a rising global gene and cell therapy Contract Development and Manufacturing Organisation (CDMO).

The business outsources its capabilities to other drug developers via its LentiVector platform. This drastically reduces the cost of developing gene and cell therapies. So, it’s not surprising that pharmaceutical titans like Bristol Myers Squibb, AstraZeneca, and Novartis are all active customers.

These big pharma clients pay ongoing milestone fees throughout development, as well as a royalty on sales for any drug that makes it to market. Most of the current drug pipeline using LentiVector remains relatively early-stage. However, continued innovation and expansion have given the company a stronger manufacturing presence within the US market as part of its wider expansion strategy.

Investing in the US genetics industry

American genetics stocks have to navigate an equally complex regulatory environment. In the UK, all medical treatments and tests need to be approved by the Medicines & Healthcare Regulatory Agency (MHRA). In the US, approval is required by the Food & Drug Administration (FDA).

The US stock market has plenty of genetics shares listed. Here are some of the leading businesses in this space in order of market capitalisation as of January 2026:

1. Illumina (NASDAQ:ILMN) – $21.6bn market cap
2. CRISPR Therapeutics (NASDAQ:CRSP) – $5.1bn market cap
3. Fulgent Genetics (NASDAQ:FLGT) – $868.0m market cap
4. Pacific Biosciences of California (NASDAQ:PACB) – $667.2m market cap
5. Editas Medicine (NASDAQ:EDIT) – $198.2m market cap

Are genetics stocks right for you?

In 2026, genetics stocks continue to show tremendous long-term growth potential. But they remain highly volatile stocks making them a risky endeavour. Just looking at these eight UK and US genetics shares demonstrates that perfectly. 

Needless to say, individuals thinking about investing in genetics stocks need to have a high risk tolerance. While genetic research may have been around for decades, the same can’t be said for most of the stocks listed today.

Even the multi-billion-pound market cap stocks on this list are still executing fundraising efforts to fuel growth. And with a generally high failure rate within this industry, there’s a high chance most will fail in their quest to capture the multi-billion-dollar market opportunity.

Needless to say, prudent due diligence, careful research, and a diversified investing approach are critical when investing in such high-risk, high-reward sectors. By owning a basket of companies in this area, the odds of finding the future industry leader climb higher.

The post Investing in Genetics: Top UK Genetics Stocks of 2026 appeared first on The Twelfth Magpie.