It's a common stereotype that Halfling Trade Ships are a big deal. This is because they literally are a big deal. These vessels with their bizarre 'sails', their flat, broad, boxy shape, and their prominence on the docks, are so big that places they dock have rebuilt their harbours to accomodate them. People tend to call them Hulks - these enormous bulky vessels that sit in harbour for a few weeks unloading and reloading.
For perspective, most ships owned by one of the Halfling Trade Companies vary in size - they each own a fleet, after all - and a lot of those boats are for transporting things to and from the centralising Hulks. But the boats people mean when they mention this are the Hulks, and the Hulks range in size from one hundred to two hundred meters long. Each Hulk is so tall out of the water even loaded that they need special areas for loading and unloading so that they don't risk damaging nearby dock space. A fully empty Hulk can sit out of the water two and a half Long Storeys (about 10 meters). Long storeys referring to the storey height standard for the medium-sized cultures. A short storey is the measurement used by groups like halflings, kobolds and goblins who are inclined towards engineering standards, known collectively by the company as midfolk.
(Historical note: Modern freighters cap at around 400 meters long, and the largest real-world wooden ship ever to sail was the Wyoming, which was 140 meters long and lived and eventually died on its pumps, since the hull warped and distorted in rough weather.)
Technically speaking, they aren't Hulks any more - a hulk is a vessel that floats, but isn't seaworthy. That's where the Halfling trade houses got their first vessels. They bought Hulks from others, and then rebuilt them from the internals. When you need half the space to transport people, you can do a lot of reinforcing and fixing. When you can't, you can always just strip hulk A and B for parts for hulk C. This was the basis of the halfling trade vessels' whole merchant empire.
They're enormous! They're just bloody huge! And the companies that owne them are halfling companies, and they're often crewed by midfolk - so the stereotype is that these vessels are teeming with halflings, who run an elaborate trade network. This is as with many such stereotypes, completely wrong. In fact, if you ask what the three remaining great Trade Houses own the most of it's dock-side real estate. The boats are big and expensive and they own a lot of them, but if you live near a dock, almost every one of the teetering apartment buildings and broad flat flop houses near them are owned by and maintained by one of those three houses..
Because that's where almost all the workers for the Trade Houses are! They need armies of people every time a Hulk comes in, and they need a place to put them! It's very good work on a schedule that works for some people - you sign on for a minimum of two sets of unloading the vessel, then reloading it, known as a full reload. You don't get paid until the second reload is done, but you get what's called your 'stipend' - which is your 'stay out of trouble money'. You get a place to sleep, you get training and exercise, and there's always miscellaneous day labor stuff that gets added to your packet at the end, but the big dump of cash you get, you don't get until you show you can stick out for two reloads...
and the fastest reloads, in the bay north of Danube, are bimonthly. Two months of incredible boredom followed by a full week of non-stop, always-need-hands physical labor, being overseen by incredibly fussy detail oriented information managers. The joke is that they know how many grains of rice leave the boat.
It's not really a joke.
It's hard work for long term life: it's incredibly boring and if you do something that renders you unable to work while you're on contract, your pay can be severed (where they keep some of it and discharge you). This is to discourage the dock workers from doing something foolish like getting into bar brawls that make them bad at unloading the vessel when they're needed.
What makes this all the more remarkable is that these workers are represented by a union and these conditions are negotiated deals with the union in each port. Not ideal, but there's always a miserable 'it used to be worse.'
There are three major Trade Houses, and they are all still primarily owned by halfling business traders: House Jura, House Carpathia, and House Piton. There used to be a fourth house, a bigger house that was at one point responsible, they say, for one in every four coins that moved through any port around the whole continent. That house, Northumbria, collapsed under its own weight, and was eventually cannibalised by the other houses, who determined that maybe there needed to be some caps on their ambition.
(for now)
The trade houses are voracious for anything that can make them better at what they do. New technologies for loading and unloading vessels, magic for tracking the contents of containers, new types of wood for making vessels stronger and more capable of repair.
The Halfling Trade Houses are also where the idea of shares and investment came up. Each of the houses made a deal early on when they were more diversified, that rather than twenty houses that each owned a boat, everyone would own one share in everyone else's boat, and therefore, any loss of a boat would only diminish anyone by one twentieth, and could be restored, rather than a catastrophic loss that wiped out a company at a time. This was part of the transition from each boat being a home business - with a family of halflings piloting the ship they lived on around doing trades - and began the period of slow but relentless expansion of the boats.
When people say 'Halfling Trade Houses' they're not entirely wrong. The houses employ a huge number of people, but the core of administration is a network of several halfling families. To maintain this, then, any time an acquisition or promotion happens, the halflings family in charge of the company adopts their new leader - which does mean that there have been kobold, goblin and orc members of the family as well, though each of those are rare examples. Thanks to this chain of adoptions, the families persist and their reputation does.
On the other hand if you meet an orc surnamed Piton and he tries to pretend he's a big thicko, be extremely concerned that you might be being taken for an abrupt ride.
EDIT: I guess technically, the thing that the Halfling Trade Houses own the most of, it's money.
EDIT 2: Oh I didn't mention the sails.
Part of what makes the hulks so distinctive is that they don't have 'sails' the way you'd consider, despite how big they are. Instead they have an enormous set of kites that they anchor off the front (or sides) of the boat, which they fill with wind and relaunch with wind magic any time the wind slacks. It's incredibly energy efficient, and these kites are in some cases measured from edge to edge as big as the boat they're pulling. Again: There needs to be a lot of work done to make your harbour valid for a Hulk to park there.