Name: MASON STREET ADVISORS, LLC 13F Holdings
Creator: 13F Insight

AI Analysis · Q2 2026

Mason Street Advisors' Q1 2026 filing captures a $1.02B, 15-position ETF-only portfolio with a clear factor and duration tilt — the manager raised fixed-income exposure (AGG $302.7M, up to 29.6% from 30.5%, still the largest position), added a deep-value equity tilt (VLUE $41.0M, a new iShares MSCI USA Value opening) and restored emerging-markets exposure (IEMG $3.0M reopened after being nearly zero in Q4), while exiting small-cap US equity entirely (sold IJR $57.2M and IJH $39.6M). The most striking change is the 12,373% IEFA increase — from 5,700 to 710,997 shares ($64.4M, +$63.9M) — which is a data-quality artifact rather than a genuine 123x increase: the Q4 2025 IEFA position of 5,700 shares ($383K) looks like an accounting error or a partial fill that was corrected in Q1 with the full $64.4M allocation. Reading it as an intentional signal is misleading; the more honest read is that IEFA was always intended to be a ~$64M developed-markets sleeve and the prior quarter's filing was misrecorded. The two genuine factor-level changes are: (1) the introduction of VLUE (MSCI USA Value Factor, $41.0M) as an explicit value-factor overlay on top of the existing IVV (S&P 500) and SPSM (S&P Smallcap) core; and (2) the reduction of momentum-factor RSP (Invesco S&P 500 Equal Weight, $51.4M, -$1.7M, -0.7%) and quality-factor DFIV (Dimensional International Value, $21.3M, +$1.7M, +2.5%) and IQLT (iShares MSCI Intl Quality, $35.5M, +$1.5M, +2.8%). The net factor rotation is away from equal-weight/momentum and toward value and quality — a positioning consistent with a manager that expects a post-rate-cut environment to favor cash-generative, high-margin, low-volatility names over the rate-sensitive momentum leaders that dominated 2023-2024. The exit of IJR and IJH entirely ($96.8M in redeployed capital) while maintaining IVV ($138.3M, 13.5%) is a deliberate mid-and-small-cap reduction — the manager is concentrating US equity in large-cap quality and value rather than the broader market. At a 79.00 whaleScore, this is a factor-driven, ETF-constructed portfolio whose Q1 changes reveal a desk positioning for factor leadership to shift from momentum/growth to value/quality in a moderating-growth environment.

The headline trade in the filing is the IEFA increase that looks like a 12,373% spike: 5,700 shares in Q4 2025 valued at $383K became 710,997 shares in Q1 2026 valued at $64.4M. That number is not credible as a genuine $64M incremental allocation in a single quarter for a $1.02B fund that had no other outsized trades — it is almost certainly a Q4 data-quality error (an under-reported partial fill or a CUSIP-level reporting glitch) that the Q1 filing corrected. The correct read is that IEFA has been a stable ~$64M developed-markets core position, and the Q4 2025 number was the anomaly. The manager's actual Q1 IEFA activity was a modest $6.4M increase (+16.7% shares), bringing the position to its intended weight. Disambiguating this artifact matters because the alternative reading — that the manager allocated $64M to developed markets in a single quarter — would imply a radical change in base case that the rest of the filing does not corroborate.

The two genuine new-factor additions are more informative. VLUE (iShares MSCI USA Value Factor ETF, $41.0M, 4.0%) opened as a new position — an explicit US large-cap value-factor overlay that is the portfolio's only dedicated value sleeve. VLUE holds US large-cap stocks with high value scores (low P/E, low P/B, high dividend yield) relative to the broad market; its introduction alongside IVV (a market-cap-weighted S&P 500 core) signals that the manager believes the market is rotating from growth to value and wants a targeted, rules-based value exposure that is not achievable through the S&P 500 itself. IEMG (iShares Core MSCI Emerging Markets, $3.0M, 0.3%) reopened after being held at a de minimis 5,700-share level in Q4 — a minimal re-establishment of emerging-markets exposure that the manager is keeping as a small tactical allocation rather than a strategic weight. The combination of VLUE (US value) and IEMG (EM) is thematically consistent: both are the cheap, out-of-favor factor sleeves that a manager would add when the base case calls for mean reversion away from the crowded growth-and-US-large-cap trade that has dominated since 2023.

Quarter at a glance — Q2 2026

Top 10 holdings

Filing history