Script to more easily get an idea of the current value of your stock at a company.

stock-value.rb

require 'date'
require 'json'

# assume standard 4-year vesting
# ignores cliff
# ignores vesting periods, assumes daily. (watch out for this)

unless price = ARGV[1]
  puts "Must pass in price as second arg..."
  exit 1
end
price = price.to_f

def fail_grant
  puts "Must pass in grants as first arg..."
  puts 'Format: [{"shares":100000,"start":"2001-01-30"}]'
  exit 1
end

fail_grant unless grants_pre = ARGV[0]
now = Date.parse(ARGV[2]) rescue DateTime.now

begin
  grants_pre = JSON.parse(grants_pre)
  fail_grant unless grants_pre.is_a?(Array)
  grants = grants_pre.map do |g|
    start = g['start']
    year, month, day = start.split('-')
    g_end = "#{year.to_i+4}-#{month}-#{day}"
    {
      :shares=>g['shares'],
      :start=>Date.parse(start),
      :end=>Date.parse(g_end)
    }
  end
rescue Exception => e
  p e
  fail_grant
end

worth = grants.map do |g|
  range = g[:end] - g[:start]
  elapsed = now - g[:start]
  percent = (elapsed / range).to_f
  amount = g[:shares] * percent
  {shares: g[:shares], percent: percent, amount: amount.to_i}
end

worth.each do |g|
  puts "Grant is at #{(g[:percent]*100*100).round/100.0}% for #{g[:amount].to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")} shares."
  puts "At $#{price}/share, it's worth $#{(g[:amount]*10).to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")}."
  puts '-'
end

puts '---'

total = worth.reduce do |a,b|
  {
    shares: a[:shares] + b[:shares],
    amount: a[:amount] + b[:amount],
    percent: (a[:amount] + b[:amount]) / (a[:shares] + b[:shares]).to_f
  }
end


puts "Grant is at #{(total[:percent]*100*100).round/100.0}% for #{total[:amount].to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")} shares."
puts "At $#{price}/share, it's worth $#{(total[:amount]*price).to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")}."

puts '==='
puts "At completion, it'd be worth $#{(total[:shares]*price).to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1,")}."