If you're investing in the stock market and feeling tired of all the volatility, you're not alone. Companies across a variety of industries have been contending with choppiness for months on end.

While there's no way to tell when it will all start to die down, you can strengthen your portfolio right now -- ahead of when the market rebounds. If you have $20,000 to invest, here are three incredible companies to consider.

1. Vertex Pharmaceuticals

When it comes to a biotech stock with robust competitive advantages and market leadership, few can compare with Vertex Pharmaceuticals (VRTX 1.36%). Not only is it the dominant force in the multibillion-dollar cystic fibrosis treatment industry, but its four products -- Trikafta, Symdeko, Orkambi, and Kalydeco -- are the only approved CFTR modulators that have made it to market.

According to the Cystic Fibrosis Foundation, "Cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapies are designed to correct the malfunctioning protein made by the CFTR gene."  

These therapies are helping to change the way CF patients are living and, in some cases, helping them live longer. This has made CFTR modulators a revolutionary option for fighting the genetic disease, and Vertex's foothold on this market has enabled it to record significant revenue growth and profits -- as well as strong investor returns -- in the process. 

Over the trailing decade, the company has increased its annual revenue by more than 200%. In addition, Vertex's annual net income has risen by nearly 790% and its annual liquidity by well over 300%. While the S&P 500 is still trading down about 16% over the past year, Vertex shares have risen by more than 70%.  

Vertex's sustained history of growth, coupled with its lucrative portfolio of drugs and enviable pipeline of various rare disease drug candidates, makes a strong case for investors to consider buying this top healthcare stock

2. Johnson & Johnson 

Johnson & Johnson (JNJ -1.82%) hardly needs an introduction, which is one of the reasons it remains such a resilient buy in a wide variety of market environments. From Band-Aids to orthopedic plates to cancer therapies, the products that J&J makes span a broad range of consumer and medical needs that don't fluctuate with market or economic headwinds. 

Johnson & Johnson's history as a company goes all the way back to 1886, and its impeccable track record of paying and raising its dividend is so illustrious that the stock has done so for 60 years and counting. Beyond its status as a Dividend King, the stock has also delivered a total return of 220% for investors over the past decade, right around the S&P 500's total return of 230%.  

In 2021, Johnson & Johnson grew its revenue and net earnings 14% and 42%, respectively, from the prior year. And in the most recent quarter, its broad portfolio of products delivered 2% revenue growth and 22% net earnings growth from the year-ago period, a reasonable clip for a mature company of this kind.

With the company's upcoming split into a stand-alone consumer goods entity called Kenvue, and a medical device/pharmaceutical giant under the Johnson & Johnson name -- both of which will be publicly traded -- investors seeking dividends and steady growth can capitalize on the company's present and future growth stories for many years to come.

3. Intuitive Surgical

Intuitive Surgical (ISRG 1.62%) has a simple but incredibly sticky business model. As the leading developer and manufacturer of surgical robotic systems globally -- the company controls an 80% share of this fast-growing market -- Intuitive Surgical finds that its products enjoy consistent and growing demand. 

Its flagship product, the Da Vinci Surgical System, along with its Ion system, is used in a wide range of minimally invasive procedures globally. Surgical robotic systems have significant benefits for patients and providers alike. Not only can the use of surgical robotics help streamline procedures in a busy healthcare environment, but for patients these systems can enable shorter recovery times, smaller incision areas, and less pain during recovery. 

Over the past decade, Intuitive's unparalleled dominance of the surgical robotics market -- a space on track to hit a global valuation of $17 billion by the year 2031-- has enabled it to grow its annual revenue and earnings by 162% and 160%, respectively.

In the most recent quarter, while procedure volumes remain impacted in certain markets due to resurgences of COVID-19 cases, management still reported that the company's installed base of Da Vinci systems grew 13% from the prior-year period, with revenue up 11% year over year. For long-term investors, Intuitive Surgical's solid business and financials make the company an intriguing investment opportunity in the current market and well beyond.