What is investor relations

Investor Relations is the communication of information and insight between a company and the investment community. This process enables a full appreciation of the company’s business activities, strategy and prospects and allows the market to make an informed judgement about the fair value and appropriate ownership of a company.

According to Investopedia
Investor relations (IR) is a department, present in most medium-to-large public companies, that provides investors with an accurate account of company affairs. This helps private and institutional investors make informed buy or sell decisions. A company's IR department also serves as a bridge for providing market intelligence to internal corporate management.
The purpose of IR is to ensure a company's publicly traded stock is being fairly traded through the dissemination of key information that allows investors to determine whether a company is a good investment for their needs. IR departments are subdepartments of public relations (PR) departments and work to communicate with investors, shareholders, government organizations and the overall financial community.
The Function of IR Departments
IR teams are typically tasked with coordinating shareholder meetings and press conferences, releasing financial data, leading financial analyst briefings, publishing reports to the SEC and handling the public side of any financial crisis. Unlike other parts of PR-driven departments, IR departments are required to be tightly integrated with a company's accounting department, legal department and executive management team (CEO, COO, CFO).
In addition, IR departments have to be aware of the changing regulatory requirements, and advise the company on what can and cannot be done from a PR perspective. For example, IR departments have to lead companies in quiet periods, where it is illegal to discuss certain aspects of a company and its performance.
Read more: Investor Relations (IR) Definition | Investopedia 
According to Wikipedia
Investor Relations (IR) is a strategic management responsibility that is capable of integrating finance, communication, marketing and securities law compliance to enable the most effective two-way communication between a company, the financial community, and other constituencies, which ultimately contributes to a company's securities achieving fair valuation. (Adopted by the NIRI Board of Directors, March 2003.) The term describes the department of a company devoted to handling inquiries from shareholders and investors, as well as others who might be interested in a company's stock or financial stability.
Typically investor relations is a department or person reporting to the Chief Financial Officer (CFO). In some companies, investor relations is managed by the public relations or corporate communications departments, and can also be referred to as "financial public relations" or "financial communications." 
Many larger publicly traded companies have dedicated IR officers (IROs), who oversee most aspects of shareholder meetings, press conferences, private meetings with investors, (known as "one-on-one" briefings), investor relations sections of company websites, and company annual reports. The investor relations function also often includes the transmission of information relating to intangible values such as the company's policy on corporate governance or corporate social responsibility. Recently, the field has trended toward an increasingly popular movement for "interactive data", and the management of company filings through streaming-data solutions such as XBRL or other forms of electronic disclosure have become prevalent topics of discussion amongst leading IROs worldwide. The investor relations function must be aware of current and upcoming issues that an organization or issuer may face, particularly those that relate to fiduciary duty and organizational impact. In particular, it must be able to assess the various patterns of stock-trading that a public company may experience, often as the result of a public disclosure (or any research reports issued by financial analysts). The investor relations department must also work closely with the Corporate Secretary on legal and regulatory matters that affect shareholders.
While most IROs would report to the Chief Financial Officer, they will usually report to the Chief Executive Officer (CEO) and Board of Directors of the corporation. This means that as well as being able to understand and communicate the company's financial strategy, they are also able to communicate the broader strategic direction of the corporation and ensure that the image of the corporation is maintained in a cohesive fashion.
Due to the potential impact of legal liability claims awarded by courts, and the consequential impact on the company's share price, IR often has a role in crisis management of, for example, corporate downsizing, changes in management or internal structure, product liability issues and industrial disasters.
In difficult financial times IROs will want to stay visible and build relationships, be factual in tone and not too quick to make promises, focus on the long-term story and balance sheet strength (as opposed to short-term earnings growth), aggressively refute rumors and answer concerns of investors, and coordinate media relations and investor communications. Finally, IROs should remember: “The story is the business, not the stock price.”
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