McGwire's 70th HR ball plummets in value after selling for $3M

Paying millions for Mark McGwire's historic 70th home run baseball apparently wasn't the best investment decision.

Comic book artist Todd McFarlane purchased the ball for just over $3 million at auction after McGwire set the single-season home run record in 1998, but according to TMZ Sports, several sports memorabilia auction houses now estimate it to be worth as little as $250,000.

Goldin Auctions founder Ken Goldin placed the ball's current value between $250,000 and $300,000, while David Bohler of SCP Auctions estimated it could be worth anywhere from $250,000 to $400,000.

Barry Bonds ultimately broke McGwire's record when he hit 73 home runs in 2001. McFarlane also owns Bonds' No. 73 ball, which he reportedly paid about $500,000 for.

In 2010, McGwire admitted to using steroids during his big-league career.