I mainly made this to have an excuse to make big money in a way that made sense without crafting guns and selling them repeatedly.

Requires CET

Version 0.0.2

How it works:

Once you have access to V's corpo plaza apartment, look at the computer in there, it will let you interact with the "stock broker"
The stock broker is now added as a phone contact. Call him to open the stock broker menu.

At the moment, there is only one stock called Night City ETF. Every 5 seconds (real time), the value of your portfolio will change by a random small percentage (positive or negative!). The percentage is biased towards positive so that on average, you can expect ~50% gain every hour of playtime.

There are 6 stocks to invest in:

Night City ETF
The 5 companies with skyscrapers in the middle of Corpo Plaza:
Arasaka
Petrochem
Kang Tao
Militech
Biotechnica

How the stocks work:
Each stock changes by a random small percentage (positive or negative) every 5 seconds (realtime). There is a bias to the randomness so that you can expect a certain overall percentage gain (positive or negative) every 30 minutes of playtime.

Night City ETF starts off so that you expect -5% average loss per 30 minutes. EACH GIG AND CYBERPSYCHO YOU COMPLETE IMPROVES THE AVERAGE GAIN BY .5%. So once you've completed all gigs and cyberpsychos, you can expect the Night City ETF to gain around +40% every 30 minutes.

Every 30 minutes, a random trend is chosen for each of the 5 companies.
TRENDS: 
SOARING: Expected to gain 70% in 30 minutes
GROWING SLOWLY: 30%
TRADING SIDEWAYS: 0%
DECLINING SLOWLY: -10%
TANKING: -40%

You don't know how each company is trending, so if you want steady income, complete gigs and cyberpsychos and just invest in Night City ETF
If you want to play with the company stocks, you can get stock tips from various locations near the fixers, for a price. These tips will tell you the trending state of randomly chosen companies (but they wont always be reliable!) See screenshots for the exact locations.