Authorised, Issued and Treasury Shares

A company's charter says it can issue up to 500 million shares. It has actually issued 300 million of them over the years, to founders, employees, and public investors. Of those, it bought back 40 million on the open market and still holds them in its own vault, never cancelled. A quick glance at "shares outstanding" needs to know which of these three numbers you actually mean, because using the wrong one when dividing net income into earnings per share can throw the answer off by more than 10%.

Those three numbers are authorised shares (the legal ceiling written into the corporate charter), issued shares (the shares actually created and sold at some point), and treasury shares (issued shares the company later bought back and holds itself rather than cancelling). The number that matters for almost every per-share calculation — earnings per share, dividends per share, voting power — is shares outstanding: issued shares minus treasury shares.

The three layers, in order

1. Authorised shares. Set in the corporate charter (articles of incorporation) and changeable only with a shareholder vote, this is the maximum number of shares the company is legally permitted to issue, ever, without amending its charter. Most companies authorise far more than they currently need, as headroom for future stock issuance, option plans, or acquisitions paid in stock.
2. Issued shares. The subset of authorised shares the company has actually created and distributed — to founders, through public offerings, via employee stock plans, or in stock-for-stock acquisitions. Issued shares can never exceed authorised shares without a charter amendment.
3. Treasury shares. Issued shares the company has since bought back (via a buyback program, for instance) and is holding rather than retiring. Treasury shares are still "issued" in a technical sense but are not outstanding — they carry no voting rights, receive no dividends, and are excluded from the share count used in EPS and other per-share metrics.
4. Shares outstanding. $\text{Issued} - \text{Treasury} = \text{Outstanding}$ — the number that actually matters for almost every valuation and per-share calculation, since it represents shares genuinely held by outside investors, insiders, and employees.

Worked example

A company's charter authorises 500 million shares. It has issued 300 million shares over its life and has bought back 40 million of them, still held in treasury.

1. Shares outstanding. $300\text{m} - 40\text{m} = 260$ million — the number to use for EPS, market cap, and voting power.
2. Market capitalization, at a $25 share price: $260\text{m} \times 25 = 6{,}500$, i.e. $6.5 billion — note this uses outstanding shares, not the 300 million issued, since treasury shares aren't owned by outside investors and shouldn't be counted as part of the company's value held by the market.
3. Remaining headroom to issue. $500\text{m} - 300\text{m} = 200$ million shares the company could still issue without amending its charter — relevant if it's considering a large stock-based acquisition or a follow-on equity raise.
4. If net income is $650 million, EPS calculated correctly is 650\text{m}/260\text{m} = \2.50$per share — using the 300 million issued figure instead would understate EPS at$650\text{m}/300\text{m} = $2.17$, a meaningful 13% error purely from picking the wrong share count.

What this means in practice

Getting this distinction right matters most when a company has a large or growing treasury share balance from an active buyback program, since issued-share counts reported in some data feeds can lag or conflate with outstanding shares. Analysts building models pull "shares outstanding" directly rather than back into it from issued-minus-treasury when possible, but understanding the layering is what lets you sanity-check a data source or reconcile why two vendors report slightly different share counts for the same company.