Britney Spears' younger sister, Jamie Lynn Spears, has taken steps to have more control over her sister's fortune.

Jamie Lynn Spears, who in 2018 was named the trustee of her sister's estate, filed paperwork last week in which she asked that Fidelity Brokerage Services manage the SJP Revocable Trust, adding that she should serve as the custodian.

The requested action would require a judge's approval to move any funds and seems to be in line with Britney Spears' earlier request to have her estate managed by a corporate fiduciary instead of her father, James "Jamie" Spears.

When Jamie Lynn Spears was named trustee, it was stipulated that upon the pop star's death, the 29-year-old former Nickelodeon actress would distribute her sister's wealth to Britney Spears' children, Sean Preston Federline and Jayden James Federline.

Attorneys for Jamie Lynn Spears, Britney Spears, and Jamie Spears have not commented.

Last week, a judge extended to 2021 the current terms of Britney Spears' conservatorship. Jodi Pais Montgomery was appointed to serve as conservator in place of Spears' father last September, and the pop star had petitioned for Montgomery to be permanently placed in charge of her personal affairs instead of her father.

Spears' attorney also asked the court to permanently allow a "qualified corporate fiduciary" to preside over the singer's estate. Currently, Jamie Spears is the sole financial conservator.

"Britney is strongly opposed to having James return as conservator ... [and] strongly opposed to James continuing as sole conservator of her estate," the filing read, adding that Spears is not "in any way waiving her right to seek termination" of the conservatorship in the future.

By contrast, Jamie Spears, who was named as his daughter's conservator in 2008, has requested that attorney Andrew M. Wallet be reappointed as co-conservator of his daughter's person and estate, according to the Los Angeles Times. Wallet, who reportedly consented to serve as co-conservator, worked alongside Jamie Spears in the role from 2009 until last year. The newspaper reported that Wallet had said his resignation was necessary, as Britney Spears would suffer "substantial detriment, irreparable harm and immediate danger" otherwise.

For more than a decade, Britney Spears, 38, has been under a conservatorship, which means that she does not control her personal or financial affairs. Her attorney stated in court documents earlier this month that phase one of the conservatorship was considered "triage," in which her conservators "rescued her from a collapse, exploitation by predatory individuals and financial ruin." Phase two involved her return to performing, the document states, noting that over the past several years, Spears was able to "regain her position as a world-class entertainer." However, early last year, Britney Spears announced she was going on an "indefinite work hiatus."

"The third phase of the conservatorship reflects Britney's stated desire not to perform at this time," it read. "The conservatorship must be changed substantially in order to reflect the major changes in her current lifestyle and her stated wishes."