Despite substantially increasing what he’s offering to place in a group of trusts set up for his spurned heirs in exchange for canceling shares in his billion-dollar business empire that are held by those trusts, Tom Benson is still not offering a fair trade, according to the person Benson appointed to watch out for his relatives’ best interests.

Robert A. “Bobby” Rosenthal — the trustee for Benson’s daughter, Renee Benson, and her children, Rita LeBlanc and Ryan LeBlanc — said he reached that conclusion because the Saints and Pelicans owner has yet to provide any “current valuations” of his assets, a letter dated Feb. 27 explained.

Rosenthal’s lawyer, Kevin P. Kennedy, addressed that letter to one of Benson’s attorneys in New Orleans, Paul Cordes Jr.

“Mr. Benson cannot effect an exchange until the valuations have been submitted to Bobby and approved by him,” Kennedy wrote. “Certainly, an exchange for an amount to be determined in the future cannot constitute the exchange of equivalent value.”

Rosenthal’s rebuffing of the proposal came after Benson suggested swapping out the trusts’ ownership shares in the Saints, Pelicans and other assets in Louisiana and Texas in exchange for secured promissory notes totaling about $449 million, lawyers involved in the matter have said. As collateral, Benson offered up the sports franchises themselves, Zelia LLC and Bensco Inc. — holding companies for Champions Square, Benson Tower and Benson’s five car dealerships.

Benson also said he would forgive loans he made to the trusts in recent years, and he threw in a 50 percent stake in a couple thousand acres he owns in Texas, plus full ownership of a house on the property.

All of that followed an earlier attempt by Benson — blocked by Rosenthal — to pull the Saints, Pelicans and other assets from the trusts in exchange for a $427 million unsecured promissory note.

After rejecting Benson’s latest proposal, Rosenthal instructed Kennedy to return the promissory notes and the collateral assignments.

Kennedy explained that Rosenthal may ultimately accept a proper promissory note but added, “Once Bobby receives the proposed valuations, he has a fiduciary duty to the beneficiaries under the trust agreement and Texas law to ensure that the valuation is fair, which may result in a determination by Bobby that he should obtain his own appraisals.”

Kennedy’s letter to Cordes surfaced as an exhibit in a Monday night filing related to a trust in Bexar County, Texas, of which Benson has at least momentarily lost control. That trust was set up by his first wife, Shirley Benson, who died in 1980, for the benefit of their daughter, Renee.

But a Bexar County judge on Feb. 9 suspended Benson as overseer of that trust and temporarily transferred those duties to attorney Art Bayern and former San Antonio Mayor Phil Hardberger as the legal clash between Benson and his daughter moves forward. The judge instructed Bayern and Hardberger to preserve the status quo of the trust in their roles.

On Monday night, Bayern and Hardberger lodged a pleading that echoed some of the thoughts in Kennedy’s letter to Cordes, stating in part that Benson was not offering equal value for the assets he wants to reacquire that are in dispute in Bexar County.

Bayern and Hardberger contend Benson is under the mistaken belief that it is legal for him to remove hundreds of millions of dollars in assets in “exchange for a promise that he will eventually provide the trusts with the value of those assets and, if he does not, (they) may take action to reacquire the reacquired assets.”

Bayern and Hardberger’s pleading continues, “This interpretation does not comport with the spirit or the letter” of the law. It says Benson must substitute “other property with a present, real value equivalent to the value of the assets he removes.”

At least seven trusts were created in 2009 and 2012 to protect Renee Benson and the LeBlanc siblings from having to pay estate taxes on their inheritances. Rosenthal is the trustee of those trusts. The trusts are irrevocable, meaning that Benson cannot add or remove beneficiaries but is allowed to remove assets from the trust, provided he replaces them with other assets of equal value.

The Shirley Benson trust includes shares in Bensco Inc., which owns several car dealerships; a 97 percent interest in Lone Star Capital Bank; about $5 million in cash; and real estate in Louisiana and Texas. It was enveloped in a bitter legal clash between Tom and Renee Benson — who, along with her children, was barred in late December from any future dealings with the Saints, Pelicans and other assets belonging to her father.

Upon his death, the twice-widowed Tom Benson instead wants his third wife, Gayle Benson, to inherit the reins of a business empire Forbes estimates is worth almost $2 billion.

Part of Renee Benson’s response to being cut off by her father was to ask the probate court in Bexar County to suspend her father as overseer of the trust set up by her mother and instead give that function to her. The judge suspended Tom Benson but did not transfer oversight of the trust to Renee Benson.

Tom Benson is appealing his suspension as overseer of the trust established by his first wife.

Separately, Renee and her children filed a lawsuit in New Orleans Civil District Court aiming to have the 87-year-old Benson declared mentally unfit to make business decisions. Judge Kern Reese has tasked three physicians with conducting a mental evaluation of Benson. It is expected they will report their findings around mid-March.