The rich just keep getting richer

It's seven days later and after being reunited for a few days, the world-saving adventurers are relaxing at a table in their Inn: 'The Hole in the wall'. The table is loaded with food, ale and wine and everyone is happy and relaxed.
With the profit made by Sereena selling all the remaining unwanted magical loot, none of them will ever go hungry again. Frankly, they have so much, they could probably buy up a large proportion of Nom Pariel itself!
While laughing at their embarrassment of riches, a young courier turns up at their table.
"Excuse me sires. My Master has requested your presence at his townhouse tomorrow morning."
A few moments of confusion resolves itself with the realisation that this is to do with an investment they made months ago with Montebank; the silk trader.
Despite not really remembering how much they'd invested, Nitendae, Volkon and Bastien turn up at the mansion around noon the next day. There are guards at the door but upon being told of the invitation, usher the three adventurers inside.
After being escorted to a plush 'business' room, you reintroduce yourself to the silk merchant and his middle-aged but still very attractive wife.
He spreads his hands wide as he greets you.
"My friends, I am so very happy to meet you again and under such profitable circumstances."
As you talk, fine wine and sweet meats are brought in on silver platters and in glass decanters.
"After your combined, initial investment of 300 gold coins, I'm pleased to inform you that, after costs and fees, your profit is 1,500 gold!"
Volkon can't conceal his grin. Before he'd left his homelands, he'd have happily killed for a fraction of such a vast amount of gold. Now though, it seems like mere grains of sand in the desert.
The silk merchant continues on though...
"You could take it now... Or, you could reinvest it in my next trading caravan?"

Volkon: +600gp

Bastien: +600gp

Nitendae: +600gp