# Market Sentiment: What's the price next month?

Suppose a stock trades at $250. You want to know what market participants
think its price will be in 30 days. For this purpose, Zorro analyzes the current
options prices of that stock, and calculates a price probability
distribution. The result is the probability of any
future price between $200 and $300 at the option expiration day, based on the
opinions of option buyers and sellers. The most likely price is at the top of
the distribution. The underlying algorithm and usage examples are
described on
financial-hacker.com/the-mechanical-turk.

The following functions estimate
a future price from the current ask, bid, and strike prices of all option
contracts at a determined expiration date. They generate a distribution of the cumulative price probability
at their expiration. The height of a bar in the image below is the probability
that the underlying price will end up at or below the given price level on the x
axis, in the
implied opinion of option traders.

SPY January 2018,
cumulative price probability distribution ## contractCPD (int Days): int

Generates a cumulative probabililty distribution of the current asset price at
the given number of days in the future, and stores it internally. Returns the
number of option contracts used for the distribution. The
contractUpdate function must be called before.
** **
## cpd(var Price): var

Returns the cumulative probability of the given price in **0..100**
range.
The future price will be at or below the given
value with the returned probability in percent. The **contractCPD**
function must be called before.
## cpdv(var Percentile): var

Returns the price at the given percentile of the distribution. F.i. **cpdv(50)**
returns the median of the price distribution, with equal probability of a higher
or lower price. The **contractCPD**
function must be called before.

### Parameters:

**Days** |
Minimum number of calendar days for which the price distribution is
estimated. Determines the expiration date of the used options. |

**Price** |
Underlying asset price to be estimated. |

**Percentile ** |
Probability that the future price is at or below the returned value. |

### Remarks:

- For comparing price predictions with the current price in the backtest,
make sure to use the unadjusted price. If in doubt, use underlying prices
from the historical options chain by setting
**History = ".t8";**
before selecting the asset.
**contractCPD** loads the prices of all contract with the
given expiration and can be very slow with some brokers (up to 30 minutes
with IB). For speeding up price requests, call **
brokerCommand(SET_PRICETYPE,8);** when supported by the broker.

### Example:

void main()
{
StartDate = 20170101;
BarPeriod = 1440;
PlotScale = 10;
assetList("AssetsIB");
assetHistory("SPY",FROM_STOOQ|UNADJUSTED);
asset("SPY");
Multiplier = 100;
*// load today's contract chain*
contractUpdate(Stock,0,CALL|PUT);
var PriceCurrent = Contracts->fUnl;
printf("\nCurrent price %.2f",PriceCurrent);
*// what's the SPY price in 45 days?*
contractCPD(45);
var Price = 0.;
int i;
for(i = 0; i < 150; i++) {
Price += 0.01*PriceCurrent;
plotBar("CPD",i,Price,cpd(Price),BARS|LBL2,RED);
}
printf(", projected price %.2f",cpdv(50));
}

### See also:

contract, cdf
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