The March 2020 Dash For Cash

Flight to liquidity describes investors selling illiquid assets to raise cash and pile into liquid ones. March 2020 delivered the strangest possible test of that idea: the destination of the flight — the US Treasury market, the deepest, most liquid market on earth — broke down too. For about two weeks in mid-March 2020, as the COVID-19 shock hit, everyone from foreign central banks to leveraged hedge funds to mutual funds facing redemptions tried to sell Treasuries simultaneously to raise cash, and the market meant to absorb exactly that kind of stress couldn't keep up.

What actually happened

Normally, a wave of Treasury selling gets absorbed by primary dealers, who take the other side, warehouse the risk temporarily, and gradually distribute it. In March 2020, the selling wave was so large, so fast, and so broad-based — coming from multiple types of sellers at once, all wanting cash immediately — that dealers hit balance-sheet limits (post-financial-crisis regulation caps how much risk a dealer can warehouse relative to its capital) and couldn't absorb any more. Bid-ask spreads in Treasuries, normally near their tightest in the entire market, widened by an order of magnitude. Depth collapsed. Yields, which should move smoothly and inversely with prices in a well-functioning safe-haven market, instead became volatile and, for a stretch, moved the "wrong" way — Treasury prices fell (yields rose) even as risk assets were also crashing, the opposite of the usual flight-to-safety pattern, because everyone was selling everything, including the asset meant to be the safe harbor.

Worked example

In calm conditions, on-the-run 10-year Treasury bid-ask spreads trade around a fraction of a basis point, with deep size available at the touch. During the worst days of the March 2020 dash for cash, measures of Treasury market depth (the size available near the top of book) fell to roughly a tenth of normal levels, and effective spreads widened several-fold — some measures showed 10-year Treasury bid-ask spreads roughly 5-10x their typical level. The Federal Reserve responded with unprecedented scale: it announced purchases of Treasury and agency mortgage securities "in the amounts needed to support smooth market functioning," ultimately buying hundreds of billions of dollars of Treasuries within weeks, explicitly citing market functioning — not just monetary stimulus — as the goal. Liquidity conditions began normalizing only after that intervention, illustrating that the market couldn't self-heal fast enough without outside balance sheet stepping in.

What this means in practice

The episode became a landmark case study for regulators and market structure researchers because it showed that even the market everyone treats as the ultimate liquid safe haven has finite absorption capacity, bounded by dealer balance-sheet constraints, and can break down when stress is broad enough and fast enough. It reshaped thinking on Treasury market resilience, driving post-crisis reforms aimed at central clearing and all-to-all trading platforms meant to reduce reliance on dealer balance sheets during future stress. For risk managers, the lesson is blunt: "flight to liquidity" assumes there's somewhere liquid to fly to, and March 2020 showed that assumption can fail precisely when it matters most.