Britney Spears' guardians want to change the way her money is invested.

The 'Scream & Shout' singer - whose finances and personal welfare are still under the legal control of her father Jamie Spears and lawyer Andrew M. Wallet via a court-ordered conservatorship following her public meltdown five years ago - has enjoyed a huge increase in her personal wealth following a number of solid investments, and the co-conservators filed court papers in Los Angeles on Friday asking the judge to allow them to change the way they invest her money so her finances continue to grow.

In an ex parte petition, seen by RadarOnline.com, the popstar's father and lawyer asked to modify their current investment strategy because of 'changing market conditions'.

Britney - who shares sons Sean Preston, seven, and Jayden James, six, with her ex-husband Kevin Federline - also has some of her huge fortune held in SJB Trust accounts for her children when they are older.

The 31-year-old singer is estimated to have earned a personal fortune of $58 million over the course of her career.

Her money is invested by Morgan Stanley Smith Barney and Merrill Lynch and the conservators want the investment firms to be able to change their strategy.

They asked the court to approve that 50-90% of her earnings go into fixed income, five to 35% goes into equities and up to 20% be made available for alternatives such as hedge funds and real estate funds, which was not previously allowed.

Britney recently had her new boyfriend David Lucado undergo a background check and sign a confidentiality agreement before she agreed to go on a date with him, following her split from her fiance Jason Trawick in January.