, had the same Standard and Poor's credit rating as the US government. That period of perplexing parity ended just after 1pm on Monday, when S&P, confirming it would move quickly on rating downgrades this time following a near record plunge in the price of oil last week, downgraded Exxon from AA+ to AA as Exxon's "Lower Oil Price Assumption Weakens Cash Flow/Leverage Metrics"; and since the outlook is negative, it means more downgrades are coming.

Highlights from the downgrade below:

U.S.-based integrated oil company Exxon Mobil Corp.'s cash flow/leverage measures fell well below S&P's expectations for the rating in 2019, and with lower oil and natural gas prices, low refining margins and weak chemicals demand anticipated over the next two years, the rating agency expects measures to remain weak without a significant change in the company's financial plans.

S&P revised its estimates to reflect the recent reduction in our crude oil and natural gas price deck assumptions.

As a result, S&P is lowering its issuer credit rating and unsecured debt ratings on ExxonMobil to 'AA' from 'AA+'.

The negative outlook reflects the potential for a further downgrade if the company does not take adequate steps to improve cash flows and leverage over the next 12 to 24 months, in order to bring funds from operations (FFO)/debt closer to 60% and debt to EBITDA to about 1.5x for a sustained period.