Primary vs Secondary Markets

The distinction is about where the money goes.

Primary market: the company issues new shares and receives the proceeds. Capital flows from investors to the business.

Secondary market: investors trade existing shares with each other. The company receives nothing and its share count is unchanged.

Almost all trading volume is secondary. A company might do a primary issuance once a decade and have its shares trade millions of times a day in between.

Why the secondary market matters to issuers

If companies get no money from secondary trading, why do they care about it? Because liquidity lowers the cost of capital.

Investors demand compensation for illiquidity. If buying shares meant being unable to sell them, they would pay much less for the same cash flows. A liquid secondary market means a lower required return, which means a higher price at issuance and cheaper capital for the company.

The IPO

An initial public offering takes a private company public. The mechanics matter because they are frequently asked about.

Underwriters (investment banks) assess demand, build a book of interest, and set an offer price. Shares are allocated to institutional investors at that price, and trading begins.

IPOs are typically underpriced: the first-day close often exceeds the offer price, sometimes substantially. That gap is money the company did not raise. Explanations include compensating investors for committing without knowing where it will trade, and the underwriter's incentive to ensure the deal is fully subscribed. Whether the size of the discount is justified is a long-running argument.

Alternatives have grown in response. A direct listing skips underwriting and new issuance, letting existing shares trade. A SPAC merges a private company into an already-listed shell.

Follow-on issuance

Companies return to the primary market after listing, and each route has different implications.

Secondary offerings issue new shares, raising capital but diluting existing holders. The share price usually falls on announcement, partly from dilution and partly from the signal: management issuing equity may believe the shares are expensive.

Rights issues offer existing shareholders the chance to buy new shares at a discount, which avoids dilution for those who participate.

Buybacks are the reverse: the company purchases its own shares, reducing the count and increasing each remaining holder's claim. See corporate actions.

What a trader watches

Primary events are predictable, dated flow, which makes them tradable.

An IPO creates a new instrument with no trading history, so pricing it is genuinely hard and spreads are wide in the early days. Index inclusion follows later and forces mechanical buying from index funds. Lock-up expiries release insider shares onto the market on a known date, frequently pressuring the price.