Maybe/app/models/issue/prices_missing.rb

class Issue::PricesMissing < Issue
  store_accessor :data, :missing_prices

  after_initialize :initialize_missing_prices

  validates :missing_prices, presence: true

  def append_missing_price(ticker, date)
    missing_prices[ticker] ||= []
    missing_prices[ticker] << date
  end

  def stale?
    stale = true

    missing_prices.each do |ticker, dates|
      next unless issuable.owns_ticker?(ticker)

      oldest_date = dates.min.to_date
      expected_price_count = (oldest_date..Date.current).count
      prices = Security::Price.find_prices(ticker: ticker, start_date: oldest_date)
      stale = false if prices.count < expected_price_count
    end

    stale
  end

  private

    def initialize_missing_prices
      self.missing_prices ||= {}
    end
end