(to) hold someone's feet to the fire (YourDictionary)
(idiomatic) To maintain personal, social, political, or legal pressure on someone in order to induce him or her to comply with one's desires; to hold someone accountable for his or her actions.
Investors are pressuring the oil companies.
Elyse Bruce in her article Feet to the Fire on her blog Idiomation adds:
Of special note is the fact that in medieval Europe, trial by ordeal (also known as judicium Dei) was a trial based on the premise that God would help the innocent by performing a miracle and save the accused. One such trial was to hold the accused’s feet to the fire. If the feet were unburned, or if they healed within 3 days of being held to the fire, it was taken as a sign that God had intervened on behalf of the accused, thereby proving his or her innocence. Of course, most either confessed to the crimes to which they were accused or died as a result of the trial. It was a favorite ordeal of the Spanish Inquisition (1478 – 1834) which replaced the Medieval Inquisition begun in 1184.
The fact that the idiom was used with quotation marks in the 1961 report indicates that it was an idiom that was not necessarily well-known although it was part of the language at the time. It is therefore reasonable to assume that it came into vogue in the years leading up to 1961. Idiomation therefore pegs the idiom to some time after WWII, and most likely some time in the 1950s.
The meaning has thus changed significantly over time.
meta: As for cash flow, Google the term.