A tool for understanding and calculating how both forward and reverse stock splits affect the number of shares owned and the price per share

investment_stock_splits.py

#!/bin/env python3

from enum import Enum

class StockSplit(Enum):
    REVERSE = 1
    FORWARD = 2

def main():
    # Choose StockSplit.REVERSE or StockSplit.FORWARD based on the type of stock split.
    stock_split_type = StockSplit.FORWARD
    # 2-for-1 forward split
    stock_split_type = StockSplit.FORWARD
    ratio_starting_shares = 1
    ratio_ending_shares = 2

    shares_owned_pre_split = 100
    share_price_pre_split = 100

    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

def stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split):
    if stock_split_type == StockSplit.FORWARD:
        shares_owned_post_split = shares_owned_pre_split * ratio_ending_shares
        share_price_post_split = share_price_pre_split / ratio_ending_shares

        print(shares_owned_post_split)
        print(share_price_post_split)
        print(f"In a {ratio_ending_shares}-for-{ratio_starting_shares} forward split...")
        print(f"You started with {shares_owned_pre_split} share(s) at ${share_price_pre_split} and you now have {shares_owned_post_split} share(s) at ${share_price_post_split}")

    elif stock_split_type == StockSplit.REVERSE:
        split_ratio = ratio_ending_shares / ratio_starting_shares
        shares_owned_post_split = split_ratio * shares_owned_pre_split
        share_price_post_split = share_price_pre_split * ratio_starting_shares

        print(split_ratio)
        print(shares_owned_post_split)
        print(share_price_post_split)
        print(f"In a {ratio_ending_shares}-for-{ratio_starting_shares} reverse split...")
        print(f"You started with {shares_owned_pre_split} share(s) at ${share_price_pre_split} and you now have {shares_owned_post_split} share(s) at ${share_price_post_split}")

def test_scenarios():
    # https://www.wallstreetprep.com/knowledge/reverse-stock-split/
    # 1-for-10 reverse split
    stock_split_type = StockSplit.REVERSE
    ratio_starting_shares = 10
    ratio_ending_shares = 1

    shares_owned_pre_split = 200
    share_price_pre_split = 0.90

    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

    # 1-for-8 reverse split
    stock_split_type = StockSplit.REVERSE
    ratio_starting_shares = 8
    ratio_ending_shares = 1

    shares_owned_pre_split = 200
    share_price_pre_split = 14

    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

    # https://www.wallstreetprep.com/knowledge/stock-split/
    # 2-for-1 forward split
    stock_split_type = StockSplit.FORWARD
    ratio_starting_shares = 1
    ratio_ending_shares = 2

    shares_owned_pre_split = 100
    share_price_pre_split = 100

    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

    # 10-for-1 forward split (e.g. Nvidia )
    stock_split_type = StockSplit.FORWARD
    ratio_starting_shares = 1
    ratio_ending_shares = 10

    shares_owned_pre_split = 1
    share_price_pre_split = 1_258.30
    
    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

    # 5-for-1 forward split (e.g. ServiceNow )
    stock_split_type = StockSplit.FORWARD
    ratio_starting_shares = 1
    ratio_ending_shares = 5

    shares_owned_pre_split = 1
    share_price_pre_split = 813.43
    
    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

    # 1-for-5 reverse split
    stock_split_type = StockSplit.REVERSE
    ratio_starting_shares = 5
    ratio_ending_shares = 1

    shares_owned_pre_split = 10
    share_price_pre_split = 125
    
    stock_split_calc(stock_split_type, ratio_starting_shares, ratio_ending_shares, shares_owned_pre_split, share_price_pre_split)

if __name__ == "__main__":
    main()