Strategy’s (MSTR) senior perpetual preferred stock, STRF, is increasingly standing out as the company’s most successful credit instrument since its launch in March.

Trading at $110, STRF has risen 36% from issuance and has rebounded 20% from its Nov. 21 low of $92. That date also marked bitcoin’s local bottom near $80,000, highlighting the strong correlation between STRF and bitcoin.

STRF occupies the top tier of Strategy’s preferred structure. It pays a fixed 10% annual cash dividend and features governance rights plus penalty based step ups if payments are missed. Even with its premium pricing pushing the effective yield down to about 9.03%, demand remains strong due to the security’s senior protections and long duration credit profile.

In late October, executive chairman Michael Saylor highlighted a growing credit spread between STRF and the junior STRD. The spread measures the extra yield investors demand to hold higher risk junior securities, which is now at 12.5%. At the Nov. 21 low, that differential widened to an all time high of 1.5 as investors crowded into senior exposure, STRD was trading as low as $65. The spread has since normalized to around 1.3.

Divergence is now visible across Strategy’s preferred suite. STRC, has seen four dividend rate increases to sustain investor interest.

Strategy’s equity has also rebounded, climbing from a Dec 1 low of $155 to about $185, reflecting improved sentiment across both the company’s balance sheet and the bitcoin market since announcing a $1.44 billion cash buffer resevere for the preferred dividend payments.