the goldman sachs group , inc . and subsidiaries management 2019s discussion and analysis the table below presents our average monthly assets under supervision by asset class . average for the year ended december $ in billions 2017 2016 2015 .
in billions for 2017 , 2016 , and 2015 , what was the average in alternative investments?
operating environment . during 2017 , investment management operated in an environment characterized by generally higher asset prices , resulting in appreciation in both equity and fixed income assets . in addition , our long- term assets under supervision increased from net inflows primarily in fixed income and alternative investment assets . these increases were partially offset by net outflows in liquidity products . as a result , the mix of average assets under supervision during 2017 shifted slightly from liquidity products to long-term assets under supervision as compared to the mix at the end of 2016 . in the future , if asset prices decline , or investors favor assets that typically generate lower fees or investors withdraw their assets , net revenues in investment management would likely be negatively impacted . following a challenging first quarter of 2016 , market conditions improved during the remainder of 2016 with higher asset prices resulting in full year appreciation in both equity and fixed income assets . also , our assets under supervision increased during 2016 from net inflows , primarily in fixed income assets , and liquidity products . the mix of our average assets under supervision shifted slightly compared with 2015 from long-term assets under supervision to liquidity products . management fees were impacted by many factors , including inflows to advisory services and outflows from actively-managed mutual funds . 2017 versus 2016 . net revenues in investment management were $ 6.22 billion for 2017 , 7% ( 7 % ) higher than 2016 , due to higher management and other fees , reflecting higher average assets under supervision , and higher transaction revenues . during the year , total assets under supervision increased $ 115 billion to $ 1.49 trillion . long- term assets under supervision increased $ 128 billion , including net market appreciation of $ 86 billion , primarily in equity and fixed income assets , and net inflows of $ 42 billion ( which includes $ 20 billion of inflows in connection with the verus acquisition and $ 5 billion of equity asset outflows in connection with the australian divestiture ) , primarily in fixed income and alternative investment assets . liquidity products decreased $ 13 billion ( which includes $ 3 billion of inflows in connection with the verus acquisition ) . operating expenses were $ 4.80 billion for 2017 , 3% ( 3 % ) higher than 2016 , primarily due to increased compensation and benefits expenses , reflecting higher net revenues . pre-tax earnings were $ 1.42 billion in 2017 , 25% ( 25 % ) higher than 2016 versus 2015 . net revenues in investment management were $ 5.79 billion for 2016 , 7% ( 7 % ) lower than 2015 . this decrease primarily reflected significantly lower incentive fees compared with a strong 2015 . in addition , management and other fees were slightly lower , reflecting shifts in the mix of client assets and strategies , partially offset by the impact of higher average assets under supervision . during 2016 , total assets under supervision increased $ 127 billion to $ 1.38 trillion . long-term assets under supervision increased $ 75 billion , including net inflows of $ 42 billion , primarily in fixed income assets , and net market appreciation of $ 33 billion , primarily in equity and fixed income assets . in addition , liquidity products increased $ 52 billion . operating expenses were $ 4.65 billion for 2016 , 4% ( 4 % ) lower than 2015 , due to decreased compensation and benefits expenses , reflecting lower net revenues . pre-tax earnings were $ 1.13 billion in 2016 , 17% ( 17 % ) lower than 2015 . geographic data see note 25 to the consolidated financial statements for a summary of our total net revenues , pre-tax earnings and net earnings by geographic region . goldman sachs 2017 form 10-k 63 .