We reveal this year's best-performing shares on the Dow, S&P 500 and NASDAQ indices in the US, as well as the top gainers in the UK's FTSE 100 and 350, Australia's S&P/ASX 200 and Canada's S&P/TSX. All information correct as of 3 December.

McDonald's stock hit an all-time high earlier this year. One of the strongest performers on the Dow 30, the fast-food giant is enjoying buoyant sales and has replaced thousands of cashiers with kiosks in 2017, boosting profits considerably.

Apple has had a stellar 2017. The tech colossus, which is poised to become the world's first trillion-dollar company by the end of the year, reported better than expected fourth quarter earnings last month on the back of strong iPhone, Mac and Apple Services sales.

The second best performer on the Dow, Caterpillar stock hit an all-time high this year, buoyed on by a construction boom in China and increased demand from the US gas compression industry. The heavy-equipment maker's profits have surged as a result, working wonders for its share price.

Back home, Intertek Group has also seen its share price increase significantly on the FTSE. The London-based firm, which specialises in product testing, has been turning over bumper revenues in 2017, up an impressive 10% on the previous year.

The UK's largest payment processing company is this year's second-best performer on the FTSE 100. Worldpay reported a sharp upsurge in revenue and profits this year thanks to a substantial increase in the number of transactions it performs.

This year's top performer on the Dow, Boeing stock has been soaring throughout 2017. Increased aircraft production and hugely improved cash flow help explain the sensational share price rise.

Out of all the firms included in the FTSE 100, NMC Health has performed the most robustly so far this year, with its stock price gaining 83%. The Abu Dhabi-headquartered hospital and clinic operator has been flourishing in 2017 and its market value is going through the roof.

PayPal has been riding high in 2017 and its share price has risen by 87% since the beginning of the year. The online payment processing company has posted financial results that have surpassed all expectations.

Its share price up a very respectable 88% since the beginning of January, Vertex Pharmaceuticals, a pioneer in the treatment of cystic fibrosis, is one of the strongest performers on the S&P 500 this year to date.

This British engineering company is one of this year's strongest FTSE 350 performers. Renishaw's share price has more than doubled in 2017 as the company reported a 97% increase in earnings per share and posted positive forecasts for 2018.

NRG Energy saw off an abysmal 2016 to recover its share price this year. The second best performer in the S&P 500, the Texas and New Jersey-based firm agreed to sell its renewable energy assets earlier in the year to offset massive debts, and the company share price spiked as a result.

The legal cannabis industry is taking off in a big way in North America, and Canada's Canopy Growth is one of the top gainer's in the nation's S&P 500 index. The medical marijuana company has seen its share price attain epic highs in 2017, gaining 92% since the start of the year.

The second best performer in the FTSE 350, UK-based Kazakhstan copper mining company KAZ Minerals is booming. A combination of increased output and higher copper prices has doubled the firm's revenues in the past year.

British antivirus software company Sophos is hands-down this year's number one performer in the FTSE 350. The cyber security firm's purchase of US next-gen antivirus trailblazer Invincea and a slew of excellent financial results have sent the Sophos share price soaring.

Canadian e-commerce firm Shopify is turning over record revenues, so it's no wonder the company is the second-best performer on the S&P/TSX. Since the beginning of the year, the internet firm's share price has increased by 141%.

The best performer on Canada's S&P/TSX, Kirkland Lake Gold has been rocking the Toronto Stock Exchange all year. With the price of gold rising and production on the increase, the mining company has doubled its revenues in 2017.

Sales of Invisalign are thriving and Align Technology, the company that makes the popular clear dental braces, posted record high revenues to date in 2017. Boasting a share price boost of 160% since the start of January, the orthodontics device manufacturer is this year's top performer on the S&P 500.

Fuelled by increased demand for Australian dairy products in China, Bega Cheese is this year's second-best performer in the country's S&P/ASX 200 index.

The top performer on Australia's S&P/ASX 200 is also a dairy firm. The a2 Milk Company's share price has been trending upwards throughout the year. Again, increased demand from China has boosted the company's fortunes hugely.

Super-innovative biopharma and tech companies listed in the NASDAQ index are this year's most spectacular gainers. The share price of biopharma firm AVEO has risen by a hefty 361% since the beginning of January.

Another American biopharma company that is soaring on the NASDAQ index, Opiant develops therapies that treat drug addiction and eating disorders. Its share price has jumped by 467% in 2017.

The share price of US biotech firm XOMA has risen by an enormous 530% this year. The cutting-edge company is leading the way in specialised antibody-based therapeutics, and has been enjoying significant growth.

South Korean online gaming company Gravity is this year's third-best NASDAQ performer. The company that created Ragnarok, the popular multiplayer online role-playing game, has seen its share price soar by 578% in 2017.

Marinus Pharma is a US biopharmaceutical firm that develops drug treatments for a variety of neurological disorders. A series of positive clinical study results in 2017 has helped push the company's share price into the stratosphere, making it the second-best NASDAQ performer of the year.

The best performer in the NASDAQ index, PolarityTE stock has skyrocketed this year. One to watch, the game-changing biotech firm is in the process of developing revolutionary tissue-regenerating technology.