State Street Global Advisors today announced index changes to four of its SPDR Portfolio ETFs.

The changes, which are effective as of January 24, are as follows (tickers remain unchanged):

• SPDR Portfolio Mid Cap ETF and S&P 1000 Index changed to SPDR Portfolio S&P 400 Mid Cap ETF and S&P MidCap 400 Index. The ticker is SPMD and the expense ratio is 0.05%.

• SPDR Portfolio Small Cap ETF and SSGA Small Cap Index changed to SPDR Portfolio S&P 600 Small Cap ETF and S&P SmallCap 600 Index. The ticker is SPSM and the expense ratio is 0.05%.

• SPDR Portfolio Total Stock Market ETF and SSGA Total Stock Market Index changed to SPDR Portfolio S&P 1500 Composite Stock Market ETF and S&P Composite 1500 Index. The ticker is SPTM and the expense ratio is 0.03%.

• SPDR Portfolio Large Cap ETF and SSGA Large Cap Index changed to SPDR Portfolio S&P 500 ETF and S&P 500 Index. The ticker is SPLG and the expense ratio is 0.03%.

The index switch means that the $3.6 billion SPLG fund now shares the same underlying index as the SPDR S&P 500 ETF (SPY), by far the largest ETF in the land with assets north of $311 billion. That fund has an expense ratio of 0.09%.