It's not too clear what the question actually is, but public and private US corporations are held to different public-reporting standards regarding their taxes; the former need to apply GAAP, the latter do not:
A publicly traded corporation is required by law to disclose information about the company’s financial performance to its shareholders and the Internal Revenue Service. Although both private and public corporations are subject to the same reporting requirements under generally accepted accounting principles (GAAP), the standards largely apply to public companies. Many of the rules are not applicable to private companies, some of which elect to use income tax basis accounting rather than GAAP accounting for preparing financial statements they need to file a tax return. [...]
Any company that trades stock on a U.S. stock exchange must file quarterly earnings reports. The Securities and Exchange Commission -- a government commission that protects investors -- receives the reports. Since the goal of a public company is to increase profits for its shareholders, a publicly traded company is required to make complete financial statements available to its shareholders. Public companies typically follow GAAP principles and standards when recording tax and accounting information they use in preparing financial statements. [...]
Unlike publicly traded companies, a private company does not seek financing from shareholders in the general public so is not required to publicly disclose its financial position. Privately owned companies typically rely on private sources of funding when they need to raise capital. In that case, external users of private company financial reports may include bankers and investors. Although the U.S. Securities and Exchange Commission requires publicly traded companies to comply with GAAP standards, private companies are not required to utilize GAAP financial disclosure principles. Private companies that prepare financial statements primarily to report revenue for tax purposes do not need the more complex financial statements required under GAAP rules. [...]
Many of the accounting principles under GAAP are aimed at public corporations, as they are intended to ensure the fairness of U.S. securities markets. Financial reports provide shareholders with reliable financial information to help them make informed decisions about whether to buy or sell shares of stock. Private companies that are small to moderate in size tend to focus more attention on short-term cash flow planning, as they have fewer resources with which to work. Such companies are accountable to the IRS and not to the SEC or any other agency or entity, but they may nonetheless publish annual financial statements for internal use and to provide to external users such as bankers and creditors.
This GAAP tax data is published in the company's 10-K form (filed with the SEC), normally under items 6 and 8. You can look at an example; search for "taxes on income" in the document. They may even calculate their effective tax rate (for you), e.g.
If anybody wonders what the large 2017 charge was for... it was for undistributed earnings from foreign subsidiaries repatriated after TJCA.
I'm not entirely sure about this, but one article says a shareholder in a corporation that is not publicly traded may ask to see the corporation's tax records (on site), but such requests may be denied, and the only recourse is a civil lawsuit. I guess it's left somewhat vague because legislation in this matter may differ from state to state, i.e. there probably aren't any federal regulations covering this.
