Liquidity-Seeking Algorithms

A scheduled algorithm like VWAP commits in advance to trading roughly $X$ shares every five minutes, whether or not there's anyone to trade with. A liquidity-seeking algorithm makes no such promise — it constantly scans lit exchanges and dark pools for wherever size is actually available right now, and adapts its own pace to match, trading fast when liquidity shows up and going quiet when it doesn't.

A worked order, minute by minute

A trader needs to buy 50,000 shares with a liquidity-seeking algorithm running over the next hour.

Minute 1–3: the algorithm sends small IOC orders (see Time In Force: Day, GTC, IOC And FOK) probing three dark pools in sequence. Pool A returns nothing, Pool B fills 2,000 shares at the midpoint with no market impact at all, Pool C returns nothing. 2,000 done, 48,000 to go, zero footprint left on the lit market.

Minute 4: the lit book at the touch suddenly shows 8,000 shares offered — much more than usual, a sign a large seller just arrived. The algorithm recognises the opportunity and takes 6,000 of it aggressively, well above its "normal" pace for that minute, judging that the marginal cost of taking liquidity now is lower than waiting and potentially missing it. 8,000 done, 42,000 to go.

Minute 5–15: no unusual size appears anywhere. The algorithm reverts to a slow, passive posture — resting small pegged orders at the touch rather than crossing the spread — trading only about 3,000 shares over eleven minutes, deliberately conserving the rest of the order rather than forcing trades into a thin market.

By the end of the hour the algorithm has traded in bursts tied to when liquidity actually appeared, not on a fixed per-minute quota — exactly the opposite behaviour of a schedule-driven algorithm, which would have kept forcing roughly 833 shares per minute regardless of what the book looked like.

Where it's used. These algorithms are the natural choice for orders without a strong urgency signal, where minimising footprint matters more than finishing on a schedule — a fund unwinding a large position patiently, for instance. They lean heavily on Detecting Hidden Liquidity to find size that isn't displayed, and on Sourcing Dark Liquidity specifically for routing logic across venues that don't show a public book at all.