October saw a 32.37% jump in the valuation, marking the biggest monthly increase since Fidelity helped Musk buy Twitter for $44 billion in 2022, the report said.

While that still implies X is worth nearly 72% less than what Musk paid, it’s an improvement from the summer when the value down by almost 79%. In March, Fidelity trimmed the valuation on its X holdings, following a similar cut in January.

X is not a publicly traded company, so Fidelity’s estimates are one of the few ways to gauge the platform’s value.

Meanwhile, Fidelity is also an investor in Musk’s xAI artificial intelligence startup—which is training its large language model on X data—and marked up the value of its stake by around 70% in October, according to Axios.

The report said the two increases are likely connected as X is believed to have a major stake in xAI, helping boost the value of the sister company. Indeed, xAI raised an additional $5 billion last month in a deal that almost doubled its valuation, sources told the Financial Times.

Representatives for Fidelity, X and xAI didn’t immediately respond to requests for comment.

Fidelity’s valuation estimates for November are expected to show further gains as other Musk companies soared after Donald Trump was elected president. The new administration wants to cut corporate taxes and deregulate key sectors, while Musk’s role as a trusted adviser to Trump could provide further benefits.

For example, Tesla stock soared 39% in November alone, and the Destiny Tech 100 fund, which counts SpaceX as its largest holding, shot up 269% last month.