That counterparty bids more aggressively for funds – something that is immediately observable from the pattern of bids (Table 2 and Chart 6). These examples highlight how the new ILTRs can provide an “early warning indicator” of stresses in the market, at both an individual and aggregate level. That information can be used to determine the size of and frequency of subsequent ILTRs (hence solving one important problem with the old LTRs). The ILTR supply curve The Bank’s supply curve is pinned down by its preferences – namely to provide liquidity insurance to the banking system at a price that doesn’t undermine the incentive to prudently manage liquidity. The Bank summarises its preferences using a Relative Supply Schedule (RSS). The RSS dictates how the proportion of each auction allocated to the wider collateral set responds to changes in the bids submitted, and specifically the difference between the clearing spreads on the narrow and the wider collateral set (known as the stop out spread). Chart 7 below shows some illustrative examples of an RSS. A larger stop out spread increases the proportion of the auction allocated to the wider collateral set, so the Bank’s “supply schedule” is upward sloping. Consider two simple examples. With a perfectly inelastic RSS, the Bank essentially pins down the quantity of funds it would provide against wider collateral, regardless of the bids submitted. With a perfectly elastic supply curve, the bank would, once a certain price threshold is exceeded, be prepared to allocate against all the wider collateral bids.
As we have already discussed, the first component of the insurance aspect of the framework is the reserves averaging mechanism itself, which permits banks, within reason and without penalty, to vary their reserves account balances day-to-day in the face of small and/or short-lived liquidity shocks – provided they hit their reserves target on average over the maintenance period. The second component is the OSFs which allow banks to cope with larger, expected (frictional) payments shocks day-by-day. A third component comes through longer-term OMOs to which we now turn. Longer-term Open Market Operations The most routine method for ensuring there is the correct amount of sterling in the system, consistent with reserves targets, is via short-term OMOs. Prior to the start of QE, the Bank carried out weekly short-term reverse repo operations (STRs) against a pool of “narrow” collateral comprising highly liquid sovereign or near-sovereign bonds from a small selection of countries. At that frequency, the scale of the operations could be judged fairly precisely so as to offset any autonomous factors which affected the net supply of sterling to the market. But relying solely on short term OMOs could have meant carrying out very large repo operations every week. To avoid that degree of churn, some longer term reverse repos (LTRs) were also used precrisis – at maturities from 3 to 12 months.