The top 50 from Brisbane are an integral part of the Australian economy with a combined market capitalisation of $124 billion in businesses which employ more than 150,000 people directly.

From insurance and banking to travel, gambling, retail, property and pizza, these "heavyweights" have all had their fair share of issues to deal with but remain resilient in a changing economy.

Increasingly, Brisbane's top companies are looking beyond Australian shores for growth and the likes of Flight Centre and Apollo Tourism and Leisure are in the midst of aggressive international acquisition strategies which have stamped them as emerging world players.

One of Brisbane's former market darlings, Blue Sky Alternative Investments, is proof that being a listed company is not a guaranteed escalator to greatness. In March, Blue Sky was flying high with a share price of $11.50 backed by a steady stream of positive announcements.

Short seller Glaucus Research hit them hard and within six weeks, almost $1.9 billion was carved out of its value as it share price dropped almost 80 percent, prompting a board cleanout and withdrawal of guidance.

Suncorp and Bank of Queensland faced a grilling from the financial services Royal Commission and this could well impact these two Brisbane behemoths, given the scandalous revelations of corruption and poor corporate behaviour which have torn apart AMP and damaged the reputations of the likes of Commonwealth Bank, Westpac, ANZ and NAB.

There was less turbulence for some of the Brisbane high flyers with Flight Centre moving up the list on the back of its aggressive international acquisition strategy, while Jamie Pherous' Corporate Travel Management confirmed it is also a market leader in the travel sector by climbing further up the top. Also in travel, Virgin Australia's move into profitability meant it moved into the top 10 as well.

Despite its chaotic year, NEXTDC was one of the the biggest movers of the Brisbane "heavyweights" from 16 to 10 along with Megaport which enjoyed a stellar year to move from 49 to 28. Founded by Bevan Slattery, Megaport is one of three top 50 listed companies which is linked to the serial entrepreneur, along with Superloop and NEXTDC.

Seven new companies entered the 2018 Brisbane Top 50, including Shine Corporate which returned after dropping off the list in 2017 as it doubled its first half net profit and posted some solid revenue gains.

Jumbo Interactive also made a return after an absence of five years. Lady luck has been on Jumbo's side this year as the online gaming service recorded a string of high profile jackpots which attracted new consumers to its platform while coal seam gas explorer Comet Ridge also makes a return after five years.

Takeover action has had a material effect on the Brisbane Top 50 with last year's number 4 Tatts Group swallowed up in an $11.2 billion mega-merger with Tabcorp, while civil contracting company Seymour Whyte delisted in October after it accepted a takeover bid from French construction giant Vinci.

Not all takeovers went smoothly. Brisbane-based NEXTDC was engaged in an ongoing battle with 360 Capital to takeover cloud service provider Asia Pacific Data Centres (APDC) throughout 2017, with 360 Capital eventually outbidding NEXTDC.

NEXTDC is effectively a tenant of APDC which owns three data centres in Sydney, Melbourne and Perth that house the storage for NEXTDC's operations.

As if the takeover stoush wasn't bitter enough, APDC initiated legal proceedings against NEXTDC in relation to a dispute over APDC's claimed "ongoing access rights" at three of NEXTDC's data centres.

Whether the past year has been cruel or kind to Brisbane's Top 50 Companies, there's no doubt that each has left its mark on the city's business landscape.

Find out which companies made the cut, as well as who has climbed the ranks, dropped out of the list and which CEOs are being paid the most.