Block trade

A block trade is the simplest transaction on this desk to describe and the most uncomfortable to run. A shareholder with a large holding asks several banks a single question: what will you pay me for all of it, right now, guaranteed?

The banks bid. The seller takes the highest one. From that moment the shares belong to the bank, and the seller has its money and no further interest in what happens.

Then the bank has to sell them on. If it can place them at more than it paid, it makes money. If the market falls overnight, or nobody wants that many shares, it makes a loss — and that loss is entirely its own.

This is one of the few places in banking where a bank genuinely takes principal risk on a large, sudden position in order to win business. It is why the bids are competitive, why they are made in minutes, and why the traders making them are not the same people who write the pitch books.

How the auction runs

The seller, usually through an adviser, contacts a short list of banks and gives them a deadline measured in hours. Each bank bids a price for the whole block. The seller takes the best bid and the trade is done — sometimes before the market has closed, more often immediately after.

Banks that lose have learned that a large seller exists and are restricted from acting on it. That is a real cost of running the auction widely, and it is why the list is short.

What the bank is pricing

• Size against liquidity. How many days of normal trading is this? That decides how long it will take to sell and therefore how much can go wrong.
• The hedge. Can the position be hedged overnight, and at what cost? A liquid single stock with a listed options market is a very different risk from an illiquid one.
• Who else knows. The more banks were asked, the more likely the market moves before the winner has placed anything.
• Its own inventory and appetite, which is a fact about the bank rather than about the shares.

Distribution, immediately

The winning bank places the shares with institutions, usually the same night, at a price at or slightly above what it paid. What does not place is carried on its own book and worked out over days or weeks — quietly, because a bank known to be long a large position is a bank the market can trade against.

Block or accelerated bookbuild

The two are frequently confused because they look identical from outside. The difference is who holds the risk. In an accelerated bookbuild the bank builds a book and prices whatever it finds; if demand is thin, the seller gets less. In a block the price is guaranteed first and the demand is discovered afterwards, at the bank's expense.

Why a bank bids aggressively for something it may lose money on

Because the trade is rarely the whole relationship. A bank that wins the block from a fund is the bank that fund calls next time, and the same client relationship carries advisory and financing work that is far more profitable. Block bidding is therefore priced partly as a client acquisition cost, which is one reason the winning bid can look thin relative to the risk.

This is a structural observation about how the business works, and it is not a claim about any particular firm's pricing.

The hedge, and its limits

A bank holding a large block will hedge what it can: index futures against the market component, sometimes single-stock derivatives, sometimes a partial short. None of it removes the position's real exposure, which is stock-specific and illiquid. Hedging a block is buying time rather than buying safety.

What the seller gives up

The upside. If the shares rise the next morning, that gain belongs to the bank and the investors it placed with. A seller that would rather keep that optionality runs a bookbuild instead and accepts that the outcome is not guaranteed. Which structure is right depends entirely on how much the seller values certainty, and that is a question about the seller rather than about the market.

Where blocks go wrong

• The market gaps overnight on unrelated news, and the placing price is above where the shares now trade.
• The block is bigger than the market thought, and buyers wait for the overhang rather than take part in clearing it.
• Word travels between the auction and the trade, and the price falls before the winner owns anything.
• The seller is known to have more, and buyers price the next block rather than this one.

The last is the reason large holders reduce in stages and why a lock-up on the remaining position is worth real money in the price.

The formulas above are standard textbook formulations, simplified for teaching. They explain the mechanism — they are not a valuation tool, and they will not reproduce a dealer’s price.