SPY and S and P index price differences

Right now spy is - 1.06% and the S and P is -1.63% (cnbc.com).

WHY is there a price difference between the two?

 

spx closes at 4pm. Spy does bot

 

The S&P is an index, like the Dow; so what you see is today's close on it.

SPY is an ETF, it trades until 8PM EST like a stock.

Edit.. opps, just saw Newurlmans answer.

 

Further differences include dividend schedules, management fees (not necessarily applicable to this data point)

 

It's called tracking error. There are discussions of it at Investopedia and Wikipedia.

BMK

 

That's not tracking error, SPY is one of the most liquid financial instruments in the world and the tracking error is pretty much zero.

 

I thought any difference between the price of an ETF and the index that it tracks could be considered tracking error.

The prospectus for SPY uses the term tracking risk, which to me means the risk that the ETF will fail to accurately track the index. Here's what it says:

Index Tracking Risk. While the Trust is intended to track the performance of the
Index as closely as possible (i.e., to achieve a high degree of correlation with the
Index), the Trust’s return may not match or achieve a high degree of correlation with
the return of the Index due to expenses and transaction costs incurred in adjusting the
Portfolio.

BMK

 

i.e. SPY is only an as close as an approximate value of SPX. Like some has mentioned before, SPY is NOT an index; it's an ETF i.e. a financial instrument that has its own market whereas SPX is an index that's a basket of weighted average of the companies that it's comprised of.

 

That is all true, but that particular security is so heavily traded by institutional players who can take advantage of the risk free arb with creation units that tracking error would only get above half a percent in some pretty extreme circumstances. In fact the average daily tracking error for SPY is less than .01%(https://www.google.com/amp/s/seekingalpha.com/amp/article/4228511-leveraged-etf-tracking-error) so .6% would be more than an order of magnitude greater than the average tracking error. In the OPs case it appears they were looking at a stale quote, either because SPY had stopped trading for the day or for some other reason both quotes weren't from the same instant in time.

 

SPY is what I follow the most bc as an ETF it trades premkt. Of course it's premkt value will differ from yesterday's closing S&P value