for example, can't filter Slack or Uber because not included in cik_tickers.csv. 1. Could scrape S-1 because tickers are included, 2. Might be easier to scrape nasdaq for new IPOs, CIK is included on company page - https://www.nasdaq.com/markets/ipos/activity.aspx?tab=pricings - https://www.nasdaq.com/markets/ipos/company/uber-technologies-inc-875805-89413