When the CAC 40 drops by several percentage points in a single session, we systematically see the BX4 rise in trading volumes on Euronext. This inverse leveraged tracker x2 attracts both investors looking for quick hedging and those wanting to bet on a decline. However, its daily rebalancing mechanism makes it a much more technical tool than a simple stock to buy and sell.
The daily rebalancing of the BX4: what changes everything for the holding period
The BX4 does not replicate a twofold decline of the CAC 40 over a week, a month, or a quarter. It aims for double the inverse daily movement of the CAC 40, then resets to zero the next day. This mechanism has a direct consequence on how it should be used.
Let’s take a concrete situation. If the CAC 40 loses 4% on a Monday, the BX4 gains about 8% that day. But if the market regains 4% on Tuesday, we do not return to zero: the calculation is based on a different premise each day. Over several volatile sessions, the value of the BX4 erodes even if the index returns to its starting point. This is beta slippage.
In practice, this means that one can lose money with the BX4 even if the CAC 40 ultimately declines, if the path to get there has been chaotic. The ideal holding horizon is measured in sessions, not in weeks. To delve into operational aspects, one can use the BX4 in the stock market while keeping this principle as a permanent safeguard.
Portfolio hedging strategy with the BX4
The main reason individual investors buy BX4 is not pure speculation. It is the protection of a portfolio of French stocks exposed to the CAC 40 during an identified event: earnings release, central bank decision, geopolitical tension.
Calibrating the position size
You do not hedge a portfolio of 50,000 euros in stocks with 50,000 euros of BX4. The x2 leverage means that a BX4 position representing half the value of the portfolio is theoretically sufficient to neutralize the index’s decline in a session. In reality, the correlation between an individual portfolio and the CAC 40 is never perfect.
- If the portfolio mainly contains large-cap stocks from the CAC 40, the hedge will be relatively accurate in a session
- If the positions are mid-caps or sector-specific stocks, the BX4 will only cover part of the risk
- Reducing the BX4 position size to a third or a quarter of the portfolio is often more realistic to absorb the correlation lag
The BX4 hedge works better on a diversified portfolio of blue chips than on a concentrated portfolio. This is a point that many investors discover too late.
When to enter and when to exit
You enter the BX4 before the anticipated event, ideally when implied volatility has not yet exploded. Once the shock is absorbed (generally one to three sessions), you cut the position. Keeping the BX4 “just in case” means allowing beta slippage to eat away at performance every day of sideways market.
BX4 in PEA: a tax advantage not to waste
The BX4 is eligible for the PEA, which distinguishes it from most bearish derivatives. Specifically, capital gains realized on the BX4 in a PEA of more than five years benefit from the reduced taxation of this wrapper. For an investor who already uses a PEA, it is a direct access to a short position without opening a securities account or derivatives account.
However, this eligibility has a downside: some investors hold the BX4 too long in their PEA because they want to avoid multiplying orders or because they forget about the position. Over several months of rising CAC 40, losses can be very heavy. A BX4 forgotten in a PEA during a prolonged bullish phase can lose most of its value.
Counterparty risk and discount during stress periods
The BX4 uses synthentic replication: it does not physically hold the stocks of the CAC 40 in reverse. It goes through swap contracts with a banking counterparty. Regulations govern the maximum exposure to this counterparty, but the risk exists.
During periods of high market stress, the price of the BX4 on the stock market can deviate significantly from its theoretical net asset value. A premium or discount is then observed, complicating execution. Buying a BX4 with a premium of a few percentage points because everyone rushes in at the same time degrades the hedging performance from the outset.
Placing a limit order rather than a market order reduces this risk. You set the maximum price you are willing to pay, even if it means not being executed immediately.
BX4 versus short selling: two tools, two logics
Short selling (VAD) also allows you to bet on a decline, but it requires a securities account with deferred settlement service, borrowing fees, and a theoretically unlimited loss risk if the market rises. The BX4 limits the loss to the invested amount, making it more accessible for an individual.
- The BX4 is traded like a regular stock, with a transparent order book on Euronext
- The VAD requires a broker that offers the SRD and charges specific fees
- The BX4 loses precision over time due to daily rebalancing, whereas the VAD maintains a linear exposure
For a one-off protection over a few sessions, the BX4 is simpler and less costly than the VAD. For a prolonged and calibrated short position, short selling or options remain more suitable, provided you master these instruments.
The BX4 remains a tactical portfolio management tool. Its strength lies in the speed of execution and access via the PEA. Its limitation is that time works against the position as soon as the market hesitates. Keeping this asymmetry in mind avoids unpleasant surprises.
