FRM Part II · FRM Exam Part II
Liquidity Risk: formula sheet
Key formulas
- Quoted spread
- Quoted spread = Ask − Bid
- Absolute cost of a round trip for one unit.
- Mid-price
- Mid = (Ask + Bid) ÷ 2
- Used as the reference fair price.
- Relative (proportional) spread
- S = (Ask − Bid) ÷ Mid
- Allows comparison across assets with different prices.
- Effective spread
- Effective spread = 2 × |Trade price − Mid| (for a buy: 2 × (Trade − Mid))
- Use the mid-price at the time of the trade. Measures the actual cost paid.
- Cost of liquidation (one-way)
- Cost = ½ × S × Position value
- Assumes you trade at the bid or ask, and S is the relative spread.
- Dimensions of liquidity
- Tightness, depth, resiliency (plus immediacy)
- Know which dimension a scenario describes.
- Liquidity cost (constant spread)
- LC = ½ × S̄ × P
- S̄ is the mean relative spread (spread ÷ mid-price). P is position value. You pay half the spread when closing out.
- LVaR, constant spread
- LVaR = VaR + ½ × S̄ × P
- Add the cost to VaR at the same confidence level and horizon. Use the same currency for both.
- LVaR, exogenous spread
- LVaR = VaR + ½ × (S̄ + k × σS) × P
- σS is the standard deviation of the relative spread. k is the multiplier for the confidence level, e.g. 2.33 for 99% under normality.
- Parametric VaR (input)
- VaR = z × σ × P
- σ is return volatility over the horizon. Scale daily σ by √T for T days. z is 1.645 at 95% and 2.33 at 99% (one-tailed).
- Liquidity-adjusted VaR as a ratio
- LVaR ÷ VaR = 1 + liquidity cost ÷ VaR
- Useful to state the percentage uplift from liquidity.
- Leverage ratio
- Leverage = Assets ÷ Equity
- Higher leverage means a smaller price fall wipes out equity and triggers forced selling.
- Haircut and margin
- Haircut = (Asset value − Loan) ÷ Asset value
- The haircut is the share of the asset funded by the borrower's own capital. A higher haircut cuts the loan available per unit of asset.
- Borrowing capacity
- Loan = Asset value × (1 − Haircut)
- When the haircut rises, the same assets support less funding, so the firm must sell or post more cash.
- Leverage and haircut link
- Maximum leverage = 1 ÷ Haircut
- A 5% haircut allows at most 20 times leverage on that asset. Margin spirals reduce this ceiling.
- Spiral rule
- Loss spiral: price ↓ → equity ↓ → forced sales → price ↓. Margin spiral: volatility ↑ → haircut ↑ → forced sales → price ↓
- Know which trigger starts each spiral. They reinforce each other.
- Net cash flow in a bucket
- Net cash flow = Inflows − Outflows
- A negative value is a liquidity gap (shortfall) in that bucket.
- Cumulative gap
- Cumulative gap(t) = Σ net cash flow from bucket 1 to t
- Compare it with the buffer at each horizon, not only at one date.
- Stressed outflow
- Stressed outflow = Balance × run-off rate
- Apply run-off to deposits and wholesale funding; apply draw-down rate to undrawn commitments.
- Buffer value after haircut
- Buffer value = Market value × (1 − haircut)
- Only count unencumbered assets. Haircuts are larger for riskier or less liquid assets.
- Survival horizon
- Survival horizon = Buffer ÷ stressed net outflow per period
- Valid when daily outflow is roughly constant; otherwise deplete the buffer bucket by bucket.
- Liquidity surplus or shortfall
- Surplus (shortfall) = Buffer − cumulative stressed net outflow
- A negative result means the CFP must supply extra funding.
- Liquidity Coverage Ratio
- LCR = Stock of HQLA ÷ Total net cash outflows over next 30 days ≥ 100%
- HQLA must be unencumbered and measured after haircuts and the Level 2 caps.
- Net cash outflows
- Net outflows = Total stressed outflows − min(Total stressed inflows, 75% × Total stressed outflows)
- Each outflow = balance × run-off rate. Each inflow = balance × inflow rate.
- HQLA composition limits
- Level 2 ≤ 40% of HQLA; Level 2B ≤ 15% of HQLA
- Level 1 has no cap. Level 2A haircut is 15%. Level 2B haircuts are larger.
- Net Stable Funding Ratio
- NSFR = Available stable funding (ASF) ÷ Required stable funding (RSF) ≥ 100%
- Horizon is one year. Both sides are weighted sums of balance sheet items.
- ASF and RSF weighting
- ASF = Σ (liability or capital × ASF factor); RSF = Σ (asset or off-balance-sheet item × RSF factor)
- High ASF factor means stable funding. High RSF factor means illiquid asset.
Quick revision
- Market liquidity risk is the cost or difficulty of trading; funding liquidity risk is the inability to meet cash obligations when due.
- Relative spread = (ask − bid) ÷ mid-price.
- Cost of liquidating a position = position value × half the relative spread.
- LVaR = VaR + liquidity cost, where the cost comes from the spread assumption given.
- Wider or more volatile spreads raise the LVaR add-on.
- Ordinary VaR ignores the cost of exiting a position, so it understates risk for illiquid holdings.
- Liquidity spirals: falling prices raise margins and haircuts, forcing sales, which push prices down further.
- Maturity mismatch between assets and liabilities is the core source of funding liquidity risk.
- A contingency funding plan sets triggers, responsibilities and funding sources for a stress event.
- LCR = high-quality liquid assets ÷ total net cash outflows over a 30-day stress period; the minimum is 100%.
- NSFR = available stable funding ÷ required stable funding over a one-year horizon; the minimum is 100%.
- LCR addresses short-term resilience; NSFR addresses structural funding over a longer horizon.
Common mistakes
- Using the full spread as the cost of a single sale. Fix: One-way cost is half the spread. Use the full spread only for a round trip.
- Calculating effective spread as the trade price minus mid, without doubling. Fix: Effective spread = 2 × |trade − mid|, so it is comparable with the quoted spread.
- Using the full spread instead of half the spread Fix: A mid-price valuation is half a spread away from either the bid or the ask. Use ½ × spread.
- Using an absolute spread with a relative formula Fix: Either use half the absolute spread × number of units, or convert to a relative spread first. Do not mix them.
- Treating funding liquidity and market liquidity as the same thing. Fix: Funding liquidity is about meeting obligations with cash or borrowing. Market liquidity is about trading an asset without price impact. Then explain how they interact.
- Saying a margin spiral starts with a price fall and a loss spiral starts with a margin rise. Fix: The loss spiral works through losses and lower capital. The margin spiral works through higher margins or haircuts, often due to higher volatility.
- Using the market value of buffer assets without haircuts. Fix: Apply the haircut first: value × (1 − haircut). Then compare with outflows.
- Counting encumbered assets as part of the buffer. Fix: Include only unencumbered assets that can be sold or repoed promptly.
- Counting all inflows against outflows in LCR. Fix: Cap inflows at 75% of outflows. Net outflows are at least 25% of gross outflows.
- Ignoring the 40% and 15% limits on Level 2 assets. Fix: Test the caps after haircuts every time. Excess Level 2 assets do not count.
Exam tips
- Read carefully whether the question asks for the full spread or the half-spread cost.
- Check whether the effective spread uses the mid-price at the time of trade, not the closing price.
- Match scenario wording to the dimension: price gap is tightness, order size is depth, recovery speed is resiliency.
- In stress scenarios, expect spreads to widen and the link between funding and market liquidity to feed back on itself.
- Keep currency units consistent and state the answer in the format the options use.
- Questions often give VaR already. Do not recompute it; add the half-spread cost.
- Look for the word 'exogenous' or 'constant' to pick the formula. Endogenous wording signals a conceptual question about position size.
- Check units: percentage spreads must be turned into a currency cost using position value.